These Elevating Legrests are for Drive Medical Sentra EC Heavy Duty Extra Wide Wheelchairs. The riggings will only fit these wheelchairs (Drive model #s STD26ECDDA, STD26ECDFA, STD28ECDDA, STD26ECDFA, STD30ECDDA, STD30ECDFA) and are necessary for a fully functional wheelchair.