NTR Inserts for Polespear Band Bridles or Speargun Band Wishbones 10 Spearit NTR Inserts enough for 5 Bridles / Wishbones Recommended for 1/2" polespear band bridles or speargun wishbones for up to 1/2" bands. Inserts allow for adjustment and replacement of the bridle / wishbone cord and make it easier to install bands on closed muzzle spearguns. Short 3/8" inch stem length maximizes the rubber stroke distance. Made from durable glass reinforced plastic.