I used a peice of that clear hose that they use in hospitals for the oxygen. Its a little bigger which makes be feel better about it breathing properly. From the nipple of my saito 72 i have it ran through the fus all the way back to the tail feathers 56 inches. Hardly any goo on my model at the end of the day. 10 to 12 flights. Most goo from a saito comes from that breather. the ext is fairly clean. Just my two dimes