Knuckle™

A results-focused training tool built for stretch, progression, and capacity.

Platinum-Cure Silicone Handcrafted in Canada Trusted Worldwide
Progressive Sizing Available in 11 sizes from 2.2" to 4.6" diameter.
Purpose-Built An abstract fist shape that trains your hole for the real thing.
Designed with Intent The tip finds your second hole and the circular base rotates to match your lining.
Knuckle

Choose Your Size

Looking to Fist?

22 · 25 · 28 · 30

Ready for More?

32 · 35 · 38

Doubles?

40 · 42 · 44 · 46

Knuckle 22

22

Max Ø2.2" / 5.6 cm

Max Circumference6.9" / 17.5 cm

Neck Circumference4.5" / 11.4 cm

Insertable Length6.0" / 15.2 cm

View Size → Knuckle 25

25

Max Ø2.5" / 6.4 cm

Max Circumference7.9" / 20.1 cm

Neck Circumference4.5" / 11.4 cm

Insertable Length6.5" / 16.5 cm

View Size → Knuckle 28

28

Max Ø2.8" / 7.1 cm

Max Circumference8.7" / 22.1 cm

Neck Circumference6.0" / 15.2 cm

Insertable Length6.5" / 16.5 cm

View Size → Knuckle 30

30

Max Ø3.0" / 7.6 cm

Max Circumference9.5" / 24.1 cm

Neck Circumference6.4" / 16.3 cm

Insertable Length7.0" / 17.8 cm

View Size → Knuckle 32

32

Max Ø3.2" / 8.1 cm

Max Circumference10.6" / 26.9 cm

Neck Circumference6.7" / 17.0 cm

Insertable Length7.2" / 18.3 cm

View Size → Knuckle 35

35

Max Ø3.5" / 8.9 cm

Max Circumference11.0" / 27.9 cm

Neck Circumference7.3" / 18.5 cm

Insertable Length7.5" / 19.1 cm

View Size → Knuckle 38

38

Max Ø3.8" / 9.7 cm

Max Circumference12.0" / 30.5 cm

Neck Circumference8.4" / 21.3 cm

Insertable Length8.0" / 20.3 cm

View Size → Knuckle 40

40

Max Ø4.0" / 10.2 cm

Max Circumference12.6" / 32.0 cm

Neck Circumference8.9" / 22.6 cm

Insertable Length8.0" / 20.3 cm

View Size → Knuckle 42

42

Max Ø4.2" / 10.7 cm

Max Circumference13.3" / 33.8 cm

Neck Circumference10.3" / 26.2 cm

Insertable Length8.5" / 21.6 cm

View Size → Knuckle 44

44

Max Ø4.4" / 11.2 cm

Max Circumference14.1" / 35.8 cm

Neck Circumference10.5" / 26.7 cm

Insertable Length9.0" / 22.9 cm

View Size → Knuckle 46

46

Max Ø4.6" / 11.7 cm

Max Circumference14.6" / 37.1 cm

Neck Circumference10.5" / 26.7 cm

Insertable Length9.0" / 22.9 cm

View Size →

Compare Sizes

Compare every Knuckle™ size at a glance. Measurements shown in inches.

Swipe to compare sizes →

Size Max Ø Max Circ Neck Circ Length
222.2"6.9"4.5"6.0"
252.5"7.9"4.5"6.5"
282.8"8.7"6.0"6.5"
303.0"9.5"6.4"7.0"
323.2"10.6"6.7"7.2"
353.5"11.0"7.3"7.5"
383.8"12.0"8.4"8.0"
404.0"12.6"8.9"8.0"
424.2"13.3"10.3"8.5"
444.4"14.1"10.5"9.0"
464.6"14.6"10.5"9.0"