@jmckeehan 31g is the size of the needle. Mono is in reference to the thread type (1 smooth thread), 12mm is reference to the lengrh of the thread on the outside of the needle and 16mm is in reference to the full thread length, what is outside and inside the needle if it was pulled straight (the thread is bent near the middle and one side is down inside the needle and the other side lays on the outside of the needle and is held in place by the small cotton stopper. The longer end is typically on the outside of the needle so you know when all the thread is in) PLLA is the material of thread, (7-0) is the size of the thread. When ordering threads or even when talking about them, you would have 31g 25mm PLLA threads and 30g/38mm threads. So, short answer, you have 31g/25mm and 30g/38mm threads.