Contesub Mushroom Rubber Tensioner Large is designed to smoothly hold pre or post tensioned rubbers on roller spearguns. Allows the use of a single rubber instead of two pieces, so removes the complication of tying lines in between.

Large model has a larger diameter - perfect to use with the standard size tensioner for use in double roller speargun set-ups.

Turned from a single piece of hard polymer, the super strong and smooth mushroom shape holds the band in place during the firing phase.

The tensioner is fixed with a metric screw in a stainless steel threaded insert, both supplied with it, for use in wooden spearguns. This system allows you to spot and quickly unscrew the fitting - great if you want to move it to another position, or when you need to do maintenance on your wooden speargun's surface.

Could also be used with tube spearguns, using a self tapping screw into a solid area of the speargun.

Outer diameter 50 mm - Average diameter 25 mm - Lower diameter 20 mm.