My stamp is 16 without any trailing letters

First, double check the stamp to make sure there are definitely no trailing letters (sometimes the stamp is very light).

The stamped letters following the number indicates the strength of the window balance. In general the following applies.

• The stamp "16r" is for a small window sash (less than 24" by 24") with single pane glass.
• The stamp "16hd" is for a larger window sash.
• The stamp "16tg" is for large window sashes with insulated glass.

It is important to get the correct window balance strength. If you were to choose a balance strength that was too strong for your window sash, the window sash could raise on its own. On the other hand, if you choose a balance strength that is not strong enough, your window sash may not stay up and fall down on its own.

If you have any questions about the proper balance strength you need, please contact SWISCO before you place your order. When you contact SWISCO for help determining the correct window balance strength please include the weight and size of your window sash. To weigh your window sash you must actually remove it from the window and weigh it. Also, include if your glass is single pane glass or insulated glass. Click here for the contact form for the Series 751 window sash support balance.

For window 1: S751-17 (12.5 lb sash) choose stamp option 16R.
16R will carry a window sash weight load range of 10 through 17 pounds.

For window 2: S751-25 (21.5 lb sash) choose stamp option 24HD.
24HD will carry a window sash weight load range of 18 through 22 pounds.

This information is based on 2 balances per sash. Balances are designed assuming friction in the jamb weather-strip will carry a portion of the sash weight. Suggested sash weights are approximate.