Anyị nwere ọkachamara R & D otu, 11 impregnation mmepụta ahịrị, 2 mkpuchi mmepụta ahịrị, n'ụzọ zuru ezu akpaka slitting igwe, elu mmepụta ngwá, na nkenke ule ngwá. Anyị ọkachamara na R&D, mmepụta, na ahịa nke PTFE impregnated na silicone roba ntekwasa ngwaahịa, si impregnation ka mkpuchi, si ihicha ka slitting.