We stock the popular sizes of K&S Aluminum Tubing used for Rc Boating. These are sold in a single 12" (approx 305mm) length. The sizes are the outside diameter (od). This can be used in a water cooling system when combined with silicon tubing. Pn#8102 : 1/8" x .014 x 12" Pn#8103 : 5/32" x .014 x 12" Pn#8104 : 3/16" x .014 x 12" Pn#8105 : 7/32" x .014 x 12" Pn#8106 : 1/4" x .014 x 12" Pn#8107 : 9/32" x .014 x 12" Note: Pictures 2 & 3 are for reference only. One tube per package. Tubing will telescope into the next larger or smaller size. This is useful for making bushings, sleeves, or drive shafts. See pictures 2 & 3. Loctite sleeve retainer glue is recommended for gluing brass tubing together.