38 Special /.357 Magnum Heavy Duty,Hairpin Safety, 6mm Mount Threads 303 Stainless Steel. This was the first powerhead that was designed 16 + years ago by my dad (Bud the BangStick Man) Very popular unit with gator hunters. Can be mounted on a speargun shaft, Rod & Ball Assy. or wooden dowel (pole) 1-1/4" Dia. x 6' long using our pole mount Assy AS013 "Sold Separately". ***** Rod & Ball Assembly Sold Separately ***** POWERHEAD WEIGHT: 4.1 oz.