Cylinder diameter: 100 mm/3,94 in Buoyancy: -2.42 / -1.21 Thread: ¾ NPSM Dimensions, weight and material can be found in the enclosed drawing (Files). All new cylinders are O2 clean and have undergone factory hydrostatic pressure testing which is valid for 2 years from the date of testing. Please consider that these bottles are distributed only through our US branch.