So I am currently talking to CS for ijoy, considering purchasing the limitless 24 RDA, and asked about the 510 pin, which sometimes does break off. I was told they are replaceable. Contact [email protected] by email or on their facebook page and ask for Limitless 24RDA replaceable 510 positive pin. They should be able to help you. Figure the cost at around $1. Personally, if i needed to get one, I would buy 5 at once. Better to have them and never need them, right?