Kedu ihe bụ T8Ikanamtube ìhè?"T" na-anọchi anya "tubular" (ụdị bọlbụ) na ọnụ ọgụgụ ahụ na-egosi dayameta n'ime ụzọ asatọ nke inch.A T8 nwere dayameta 1-inch (ma ọ bụ 8/8 inch), T5 nwere dayameta 5/8-inch, na T12 nwere dayameta 12/8-inch (ma ọ bụ 1-1/2 inch).
