These are manufacturer-reported material ratings, not independent measurements of every finished product. Descriptions are relative to this four-level reference.
Two silicone dildos can share the same material and still feel quite different. One may yield easily under your fingers; another may have a soft surface with firmer support underneath.
“Platinum-cured” tells you about the silicone’s curing system. To understand how a finished toy might feel, you also need to consider its hardness, dimensions, shape, and construction.
This guide explains Kervyra’s four manufacturer-reported firmness ratings—Shore A 0, 3, 5, and 25—and how to read them alongside the product itself.
On this page
What does platinum-cured silicone mean?
Platinum-cured silicone uses a platinum catalyst during curing, the process that turns the uncured material into an elastic solid. It describes how the silicone cures, not a particular level of softness. Platinum-cured silicones can have different hardness specifications, as illustrated by the different grades in Smooth-On’s silicone technical data.
The Kervyra silicone products discussed here share the same material system and basic production process. Their firmness specifications, dimensions, and layered construction still need to be considered separately.
A material name is the starting point—not a complete description of the finished toy.
What the Shore A hardness numbers mean
Shore hardness describes a material’s resistance to indentation under specified test conditions. It is different from judging how easily an entire toy bends or how it feels during use. ASTM’s durometer hardness overview explains the distinction between indentation measurements and other material properties.
Kervyra’s four reference levels use the Shore A scale, as shown in the overview above.
These are manufacturer-reported material ratings, not independent measurements of every finished product. “Medium” and “firm” are descriptions within this reference range, rather than universal labels shared by every brand.
The numbers provide a technical reference. The following comparisons give them a little personality.
Four firmness levels, four personalities
Everyday objects vary in their materials and construction. These comparisons are mental pictures of softness and resistance—not claims that a pillow, ball, or rubber block has the same Shore rating as our silicone.
Shore A 0: The Gentle One
This is the very-soft end of Kervyra’s four-level reference: the emphasis is on softness rather than resistance. Its personality is the one that gives way instead of pushing back.
That does not mean every Shore A 0 design will bend or compress identically. A broad section and a narrow section can behave differently even when they use the same silicone specification.
Shore A 3: The Even-Tempered One
Kervyra describes this level as medium. It sits between the very-soft character of Shore A 0 and the firmer character of Shore A 5.
“Even-tempered” describes its place in this range. It does not mean everyone will experience it as perfectly balanced; your reference point may be a much softer or firmer toy.
Shore A 5: The Assertive One
The comparison is about a more noticeable sense of resistance. Kervyra describes Shore A 5 as firm relative to the two lower ratings.
Its personality is more assertive, but firmness is not the same as rigidity. The length, thickness, and shape of the finished design still matter when considering how it handles.
Shore A 25: The Strong-Willed One
This is the most resistant material rating in Kervyra’s four-level reference. The comparison emphasizes support and resistance, not a claim that it feels like stone or hard plastic.
Shore A 25 can also serve a different role inside a layered design: a firmer core can sit beneath a much softer exterior.
Why the same hardness can feel different in another size
Material hardness and whole-product flexibility are not interchangeable.
As a general mechanical guide, a thicker section usually resists bending more when its material, length, and construction are otherwise comparable. A longer section can bend more readily when thickness and construction remain comparable. These are simplified principles of elasticity, not measured comparisons between every Kervyra size. The Feynman Lectures’ discussion of bending explains why both cross-section and length matter.
This is why “the larger one feels firmer” can describe an observation without meaning that the silicone itself has a higher Shore rating.
It also does not establish higher material density. Density means mass per unit volume; a larger object can contain more material without that material becoming denser. OpenStax’s explanation of density separates these ideas.
For a silicone dildo, read firmness alongside maximum width or diameter, circumference, insertable length, and changes in the profile. “Larger” alone cannot tell you how flexible a design will be.
How dual-density silicone combines softness and support
Here, “dual-density” describes a two-firmness construction: a softer silicone exterior around a firmer silicone core.
For designs specified with a Shore A 0 outer layer and a Shore A 25 core, the two ratings describe different parts of the same product. The exterior provides the softer material at the surface; the core provides firmer support beneath it.
A padded armrest is a useful mental picture. Pressing its cushion and bending the whole armrest are different actions. In the same way, surface give and overall support should be considered separately.
The thickness of the outer layer, the size of the core, and the overall shape also influence the finished feel. Two hardness numbers cannot fully describe that construction.
Check the specifications for the individual model. A “dual-density” label does not, by itself, confirm a particular pair of Shore ratings.
Reading firmness alongside real product designs
The following examples show why material ratings belong beside dimensions and construction—not in place of them.
Rovekel: a softer exterior around a firmer core
Rovekel is a dual-density realistic silicone dildo with a softer outer layer and a firmer core. Its exterior is fixed around the core; it does not slide independently along the shaft.
The S version has a maximum mid-shaft width of approximately 1.93 in / 4.9 cm and an insertable length of approximately 8.15 in / 20.7 cm.
This is a useful example of why a compressible surface does not necessarily mean an all-soft body. Compare the layered construction and the dimensions of your selected size together.
View Rovekel and its size chart
Nivaskel: the head does not describe the whole size
Nivaskel is a knotted canine dildo with a tapered head, raised contours, and a separate lower knot.
On S, the head width measures approximately 1.02 in / 2.6 cm, while the maximum knot width measures approximately 1.77 in / 4.5 cm.
Those measurements describe different parts of the same toy. Its listed medium firmness does not remove the change in width, and the head measurement alone cannot represent the full profile.
View Nivaskel and its size chart
Neruvon: three knots with different dimensions
Neruvon is a triple-knot fantasy dildo with narrower waists between three graduated knots.
On S, the knot diameters progress from approximately 1.38 in / 3.5 cm, to 1.61 in / 4.1 cm, to 1.85 in / 4.7 cm.
The changing outline is part of the design. Even within one product, the broader knots and narrower connecting sections are not geometrically identical.
View Neruvon and its size chartProduct dimensions are measured values supplied by Kervyra. Inch figures are approximate conversions. S, M, and L identify sizes within a model, not universal dimensions or experience levels.
Choosing a combination you understand
Start with the feel you are looking for: more yielding material, more resistance, or a softer surface over firmer support.
Then check the actual dimensions. Compare the widest section—not just the head—and distinguish total length from insertable length. A softer material does not make two different sizes equivalent.
Look at the construction next. A single-firmness body and a layered body answer different questions about softness and support. Use the individual product’s specifications rather than assuming that every toy with the same descriptive label is built alike.
Before use, also read the model’s cleaning, lubricant, and storage instructions. A shared material name is not a reason to borrow every care method from another product.
The aim is to understand the combination you are choosing. A realistic silhouette or an imagined form can share the same material system while offering very different proportions and construction.
Frequently asked questions
Can I compare Shore A directly with Shore 00?
Not by matching the numbers. They are different hardness scales, and measurements from different durometer types do not have a simple universal relationship. A rating of Shore 00-30 is not the same as Shore A 3 or Shore A 30. ASTM’s hardness overview explains this limitation.
Does softer silicone make a larger size equivalent to a smaller one?
No. Softness and dimensions describe different aspects of a product. A softer specification does not erase a difference in width, circumference, or length.
Is every firmness available for every Kervyra product?
Use the individual product page to check its specified firmness and available options. This guide explains the four reference ratings; it is not a promise that every model is offered in all four.
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