Palmgren  -  0-12" Heavy Duty / Copper Spindles L- Clamps Innovative spring tempered and hardened steel frames optimize high static stress loadings Dropped forged sliding clamping arm for added strength and durability Through hardened steel spindles provides greater loading capabilities and longer service life Black-oxide plated spindles that resist wear while impeding rust Replaceable swivel pads, and lfetime guarantee against breakage.