CONCAVE SPD 3.25-4'' Retention Style Silicone Nozzle

Built for experienced users who prioritize controlled insertion, secure retention, and substantial fullness, the large-format SPD Concave plugs scale the proven contour of the series into its biggest sizes yet. Each size maintains the same geometry — a long gradual taper, pronounced swell, and deep retention valley — proportionally adjusted so the feel and function remain consistent as you step up.

The extended tapered tip allows a slow, controlled entry before reaching the maximum diameter swell positioned along the shaft. After the swell, a defined retention valley helps the plug stay comfortably in place, while a wide safety flange provides dependable stability.

4" is the black item in the photo

These models are intended for advanced stretching and long-duration wear where both depth and girth are desired.

Size Options

3.25" (82.6 mm) Diameter

• Total Length: ~9" (228.6 mm)

• Insertable Length: ~7.5" (190.5 mm)

• Long gradual tapered tip

• Deep retention valley

• Wide safety flange base

3.5" (88.9 mm) Diameter

• Total Length: ~9.25" (235 mm)

• Insertable Length: ~7.75" (197 mm)

• Scaled SPD concave contour

• Secure retention profile

• Large stability flange

3.75" (95.3 mm) Diameter

• Total Length: 9.5" (241.3 mm)

• Insertable Length: ~8" (203.2 mm)

• 5.5" tapered entry section

• 2.5" retention valley

• 4.5" safety flange

4.0" (101.6 mm) Diameter — Largest in the Series

• Total Length: 10" (254 mm)

• Insertable Length: 9" (228.6 mm)

• 5.75" tapered tip

• 2.55" retention valley

• 4.7" safety flange

Features

• Scaled SPD Concave retention shape across all sizes

• Long taper for gradual insertion

• Pronounced mid-shaft swell for fullness

• Deep retention valley for secure placement

• Large safety flange for stability

Customization

Each plug is made to order and can be customized:

• Bore Type: open bore or solid (no-bore)

• Silicone Firmness: multiple softness options available

• Color: choose from our standard color selections

The solid option is especially suited for retention or focused training sessions, while open bore versions allow additional flexibility depending on preference.

Notes

Product photos are currently in progress. The design follows the established SPD Concave profile, proportionally scaled for each diameter.

Because of the extreme dimensions in the upper sizes, these plugs are recommended only for highly experienced users familiar with gradual progression.