Squeeze the putty and feel a certain amount of resistance. Stretch and fold it and feel the resistance increase even more. Non-oily and fragrance-free, the Advance(tm) Putty Kit includes one pink Base Putty and four individually packaged blue Power Packs. Additional Power Packs are sold in sets of four. Add a part or a whole Power Pack to the pink Base Putty to create a multi-phase, resistive strengthening program. The pliable Power Packs blend smoothly and easily into the Base Putty. Adding all four 9cc Power Packs increases the mixed putty to 90cc, similar to 5 oz. (142g) of TheraPutty(tm). Ideal for all squeezing and stretching hand exercises.