These single reed duck call guts are an Arkansas style, J-Frame call gut.  These guts come with a reed (the WEBFoot WCDR-1) and a piece of 1/8" cork, both of which will need trimmed to meet your needs.  Improper fitting of the cork may damage the guts beyond repair - be sure the cork is not too tight - sand or file the cork thinner if necessary.  These guts are designed to fit a .625" bored barrel and have a taper section to create the seal between the DS1 and the barrel bore.  This gut requires you to build your own exhaust "bell".  The socket in the "exhaust bell" to glue the DS1 in place should be 5/8" but one can turn that down to a size size such as 1/2" if desired, and use a smaller socket bore - or add an oring groove and use an oring instead of glue to make the assembly.

*Guts, reeds, and cork are not returnable for health safety reasons.  We have no minimum order requirements on guts for this very reason - which allows you to order one of the gut you with to try before you commit to a larger quantity.