The Mobuckle is the cellphone/battery holder/belt buckle thing used by the Kyoryugers (Which, yes, the mo is still part of Mobile phone).
Without having one in hand (never really found the appeal for it) but looking at pictures and videos, it appears to have the same belt setup as the Kamen Rider belts, but again, I don't have one so take that with enough grains of salt to make some really nice popcorn.