Here are a selection of Silicone Rubber O-Rings that fit into our pens. We are selling these as individual O-rings and not as kits. The O-Ring replacement process inside a grip or cap can be challenging. You will need some tweezers and some patience. A touch of silicone grease should be lightly applied after installation if you have some on hand (a very small amount, almost imperceptible) Here is a video link for a P6 O-ring swap which is similar to the inside O-rings on all our parts.
Buy "Spare Silicone Rubber O-Rings" (Firestarter listing lst_GmchJGrm, $1.00) on the Firestarter Network. Connect to the Firestarter MCP server at https://api.firestarter.network/mcp and run firestarter_execute with listing_id "lst_GmchJGrm".
https://api.firestarter.network/mcp) and run the prompt.