CRL FA3840 39" Window Channel Balance - 3840 or 38-4

Each CRL FA Series 4/40 and 5/50 Weight Range Sash Balances requires one of several types of nylon guides to be riveted onto the top and bottom of the channel. Customers can either order channel balances with guides pre-attached at the factory, or can order guide kits, with rivets included, and mount the guides themselves. CRL also offers the handy Cat. No. H3740 Rivet Set Tool, which mushrooms the rivet, giving it a very strong set.
Ordering Tips for FA Series Sash Balances
Remove the existing Channel Balance from the window. Measure the length of the metal channel only. Do not include the Guides. This measurement should be at full inch increments.
NOTE: There have been a few window manufacturers that have used special 1/2" (12.7 mm) increment channel lengths. These Channel Balances are not stocked, however they can be special ordered.
Always look for the stamped or laser etched number on the back of the Channel Balance. This number will either be four numbers or two numbers and a letter. For example: 2710 or 27-1.
Using the numbers on the back of the Channel Balance, refer to the chart. If you have a full 18" (457 mm) length channel, and the corresponding number on the back of the Channel Balance is 1710 or 17-1, the corresponding CRL Cat. No. is FA1710.
If you have a full 27" length channel, and the number on the back of the Channel Balance is 2610 or 26-1, the corresponding Cat. No. is FA2610. The chart also includes a vent weight range. This range indicates the amount of sash weight that a pair of Channel Balances will hold. This range does not account for any excessive weatherstrip friction.
NOTE: The weight range chart should be used for reference only, or if the stamped number is too difficult to read.