The mufflers are Dunstall Decibel replicas.
I have one on my 900CC R75/7 and it works better than the stock pattern with a 2 in 1 set up, so they must be free flowing .
The end of mine finishes about 1" short of the inner face of the rim, which is a fair bit shorter than those shown, for whatever reason, and fitted right on to the OEM bracket.
Adelaide Hills, Australia. 93 R100 GS, 77 R75/7 ,70 BSA B44VS, , 86 R80 G/S PD, 95 BMW Funduro F650 ST