Sensory Firmness Scale
Oieffur's Sensory Firmness Scale is a proprietary 4-level system that translates silicone Shore hardness ratings into real-world tactile comparisons. Because firmness is not just a material property — it changes with diameter. A 4cm shaft in Shore 00-20 platinum silicone feels noticeably firmer than a 7cm shaft in the identical material. The thinner piece has less volume to compress. The thicker piece has more give. Same silicone, different experience. This scale maps every Shore hardness and diameter combination to one of four levels, each anchored to objects you can squeeze right now — a fruit, a household item, and a part of your own body.
The Four Levels
| Level | Feels Like | Fruit Analogy | Household Object | Body Part Test |
|---|---|---|---|---|
| Soft | Dents easily under light pressure, springs back when released | Ripe avocado | Wet sponge | Pinch your earlobe |
| Standard | Noticeable elasticity, rebounds when pressed | Tomato | Eraser | Press the tip of your nose |
| Firm | Requires deliberate force to compress | Eggplant | Dry bar of soap | Press your chin |
| Hard | Nearly incompressible under normal hand pressure | Cucumber | Candle | Press the heel of your palm |
Three analogy systems cover different people. Everyone has squeezed a tomato. Not everyone has squeezed an eraser recently. But everyone can press their own nose right now. Use whichever reference makes the most intuitive sense to you.
Why Diameter Changes Firmness
This is the part most brands skip.
Shore hardness measures how a flat slab of material resists indentation. But you are not using a flat slab. You are using a cylinder with curves, texture, and varying wall thickness. When the diameter increases, the volume of silicone increases — more material means more structural support, which means it resists compression more. The material did not get harder. The geometry made it feel harder.
This is why a Small Nagaros and an XL Nagaros — poured from the same batch of silicone on the same day — do not feel the same firmness. The S feels softer. The XL feels firmer. Neither is wrong. They are different experiences from the same material.
The Lookup Matrix
Every Oieffur product's firmness level is determined by two inputs: the Shore hardness of the silicone, and the maximum diameter of the piece. The matrix below maps these combinations to one of four levels.
| Shore Hardness | Small (2.5-4cm) | Medium (4-6.5cm) | Large (6.5-9cm) | Extra Large (9-11cm) |
|---|---|---|---|---|
| Shore 0 | Soft | Soft | Soft–Standard | Standard |
| Shore 3 | Standard | Standard | Standard–Firm | Firm |
| Shore 5 | Firm | Firm | Firm | Firm–Hard |
| Shore 8 | Firm–Hard | Hard | Hard | Hard |
| Shore 10+ | Hard | Hard | Hard | Hard |
Cells with two levels (e.g., "Soft–Standard") indicate a transition zone. The actual feel depends on exact wall thickness, shape, and texture. When in doubt, we rate toward the firmer side — it is better to be pleasantly surprised by softness than caught off guard by firmness.
How to Use This Scale
Step 1: Find the product you are interested in on our Size Guide.
Step 2: Note the max diameter for your chosen size.
Step 3: Check the firmness level listed in the size chart, or use the matrix above if you want to understand why that level was assigned.
Step 4: Do the body test. If the listed level is "Standard," press the tip of your nose. That pressure and give is close to what you will feel.
If you are between two sizes and firmness matters to you: smaller = firmer, larger = softer. Same material, same product, different geometry.
A Note on Dual-Density
Dual-density products (Strong Bow, Fenrahl) have a soft outer layer over a firm inner core. The firmness level in the matrix is based on the outer layer — what your fingers feel when you squeeze. During use, the inner core provides structure that the outer layer alone would not. The result: dual-density pieces feel softer to the touch than their firmness rating suggests, but hold their shape better under pressure.
Frequently Asked Questions
What does Soft firmness feel like?
Soft firmness (Level 1) dents easily under light pressure and springs back when released. It feels similar to pressing a ripe avocado, squeezing a wet sponge, or pinching your earlobe. This level occurs in smaller diameter products (2.5-4cm) at Shore 0, or larger diameters at very low Shore values.
What does Standard firmness feel like?
Standard firmness (Level 2) has noticeable elasticity and rebounds when pressed. It feels similar to squeezing a ripe tomato, pressing an eraser, or pressing the tip of your nose. This is the most common firmness level across Oieffur's product range.
What does Firm firmness feel like?
Firm firmness (Level 3) requires deliberate force to compress. It feels similar to squeezing an eggplant, pressing a dry bar of soap, or pressing your chin. This level typically occurs in smaller sizes or higher Shore values.
What does Hard firmness feel like?
Hard firmness (Level 4) is nearly incompressible under normal hand pressure. It feels similar to pressing a cucumber, squeezing a candle, or pressing the heel of your palm. This level occurs at Shore 8-10+ across most diameter ranges.
Why does the same silicone feel different in different sizes?
Silicone firmness depends on both Shore hardness (material property) and diameter (geometry). A 4cm shaft in Shore 00-20 silicone feels noticeably firmer than a 7cm shaft in the identical material because thinner walls have less material to compress. This is physics, not a quality issue. Oieffur's Sensory Firmness Scale maps every combination so you know what to expect before you buy.
For exact dimensions and size selection guidance, see our Size Guide. For material details, see Body-Safe Materials.