Glaze Supply drywall and baypole screws with a self-drilling point and zinc finish, 3.5 x 50mm, supplied in a box of 1000. Made from hardened steel with a 3.5mm diameter and a Phillips PH2 drive, and manufactured to CE standard EN 14566. The bugle and flat head style is, in Glaze Supply's experience, well suited to baypole fastening. The self-drilling point cuts its own hole as the screw is driven in. The zinc finish gives some protection against corrosion in dry interior conditions. Check the screw length against the thickness of the materials you are fixing.