BD Spurs - DUNNETT R-Class Gull Wing Chrome Large 12.7mm legsRSPZ12 Limited Stock Item. These BD spurs mount onto the front side of bass drums and are used to anchor the drum , and decrease sliding forward when being played. Super heavy duty, with very nice chrome plating. 12. 7mm thick rods will fit into many existing floor tom leg brackets. Photo may show mounting bracket, but this part is your choice SOLD SEP. Add one of our die cast brackets to mount to your BD shell suggested 5220 round style looks and