Description: Fit for building wrist,forearm strength Fit for climbers, martial artists, athletes and anyone who wants to improve their hand strength By increasing the resistance,it will eventually allow you to build hand strength Foam sleeve function: non-slip, durable and not rubbing hands. (note: please moisten the handle with water before inserting the foam) Specification: Material: Aluminum & iron Color: silver (as shown in picture) Product size: 13.4 x 10.4 x 1.7 cm Type:100lbs /150lbs /200lbs / 250lbs / 300lbs Strength: 45kg±5 / 67kg±5 / 90kg±5 / 112kg±5 /135kg±5