GBM ni ubwoko bwogosha ubwoko bwimashini ikata ibyuma ukoresheje icyuma gikoreshwa cyane mubikorwa byinganda.
Nubwoko bugenda hamwe nibisahani bifite umuvuduko mwinshi hafi metero 1.5-2.8 kumunota. Hamwe na moderi GBM-6D, GBM-6D-T, GBM-12D, GBM-12D-R, GBM-16D na GBM-16D-R kugirango uhitemo hamwe nuburyo butandukanye bwo gukora kubwoko bwinshi bw'impapuro.
