A range of nylon rimmed plugs to suit screw sizes 3.5-12.0mm.Finish: Grey Nylon.-For medium to heavy-duty applications.-Larger sizes suitable for use with coach screws.-Often used when fixing satellite dishes.-Moulded head prevents insertion beneath the substrate surface.-Two way expansion allows use on close to edge applications. -Sprung spin fins provide a two way lock, preventing spinning and loosening from overhead applications.