This is the Riffe 9/16 inch TIE-IN Power Band - All Lengths Features:We recommend a sheet bend" knot to close/finish off Tie In Power Bands. Tie In Power Bands are used for spearguns that do not have a band slot at the muzzle area. This means you have to "tie" the bands closed after one side is inserted through the band opening. These are made to be used with our New Marauder Series wood spearguns but may also be used with any speargun on the market."