The OS strap on mufflers came in three sizes - #702 for the MAX .15, .20 and .25, #703 for the MAX-S .30, MAX-S .35 and MAX-H .40, and #704 for the MAX-H .60 and MAX-H .80. The 702 and 703 mufflers and straps are still very easy to buy and commonly come up on auction sites, but the 704 seems to be a bit harder to get hold of.