Contains: 8 guide blocks. Woodline Cool Blocks blade guides are made from non-metallic composite material, graphite impregnated phenolic laminate which contains three synthetic dry lubricants that lubricate the blade but do not make it oily. The metal to metal contact made by old metal guide blocks creates heat and friction which causes premature blade wear and breakage. Be careful how much you tighten the set screws, they are not made of steel.  When setting them up, adjust them just behind the blade's cutting teeth. You will only need 4 at a time to fit upper and lower guides. Guide blocks are 1/2" (Cool-J) or 3/8" (Cool--S) some adjustments may have to be made to ensure proper fit due to casting irregularities.