CNC Machined in Aluminium - UK made - Precision component. Cone is 10mm dia and 30mm long + 10mm long m6 thread to suit your speakers sub or rack. Vary heavy and solid. Listing is for 4 spikes. For delicate surfaces please use our self adhesive felt pads which can be found in our amazon shop. 15mm felt pads for 20mm speaker spike pads 12mm felt pads for 16mm speaker spike pads Quality product with great service.