These box-section static mixers are specifically for the S1220 - 25ml two-part clear acrylic cartridges. They will not fit any other twin cartridge.
Because of its box section it mixes more thoroughly than the spiral mixers of the same length. Consequently, there is less waste product left in the nozzle in comparison to the longer spiral nozzles with the equivalent number of mixes.
These nozzles are single use as the adhesive dries within the nozzle preventing it from being able to be re-used.
However when using multiple S1220 cartridges to the nozzle can be taken off the just used cartridge and fitted to the new one to avoid loss of product in the nozzle.