These ultra-lightweight 6061-T6 aluminum canisters are threaded to be sealed with standard low profile water bottle caps. (1.05" diameter, 1/4" high, 3 thread starts)
Each weighs in at a impressive 4.4grams empty, with an additional BP capacity of 3g sufficient for most 4" and 5" rockets.
These canisters (with cap) are 1.05" Diameter,