29 3 AS Caldwell, 29 9 AS Caldwell, 29 4 JR Caldwell

Thanks for contacting SWISCO. Take a look at our S395-30 Channel Balance. Are those spring weights for 3 different pairs of channel balances? If so, the 29 3 indicates a stamp option of 2930 and the 29 4 indicates a stamp option of 2940. The 29 9 is a bit more involved; this stamp is from an older rating system we no longer use. To know what stamp option you need to select for balances with this stamp, you must weigh your window sash. That precise weight will correspond to one of the weight ranges listed for each stamp option on the product page.