Stamp Option

Pretty sure I have the right balance selected, but my stamp is odd:
on the side of one balance (L) it says 14-5 JX CMC 7, and on the side of the other (R) it says 14-5 KX CMC 11
My sash weighs about 16 lbs; it's 33 3/4 x 17 x 2 overall.

So I don't know what stamp option I need to select.

My balances are in good shape - the plastic pieces are not cracked or broken, and the cord & spring are still very tight, but the sash still slips from time to time, and this time my take out clips broke.

Thanks for your help in selecting the right stamp option.
Jo B