Minimum Diameter BT60 (1.63" 38 mmXL) Kits
True BT60 Tubing. 1.63" We call it 38mmXL (X-tra Light) It has 1/2 mm wall! But is very strong and resilient!
These kits are minimum diameter meaning a minimum diameter retainer is highly recommended.
They come with a BT60 "Stuffer" Tube but the Booster is still slotted for maximum strength.