Conical Plug (EPDM) For M5 to M6 Screws, Ød3.2mm to ØD6.4mm, 19mm Long, EPDM (Black), Pack of 10, HBAE64-P
SGD $4.00
EPDM masking plugs have the advantage of being cheaper than silicone and are suitable for blasting processes. However, they have lower heat resistance, and can only withstand up to 150 degrees Celsius.