Yes, you can. The sizing for RingConn Gen 2 is slightly different from Gen 1 due to its thinner design; however, the dimensions of the ring and sizing kit will remain the same. Therefore, the existing sizing from RingConn Gen 1 can be used for the RingConn Gen 2. For first-time RingConn users, it is recommended that the new sizing kit be used to ensure the best fit.