Window Channel Balance 2290 23"

Thanks for posting. The stamp option of 2290 is from an older rating system we no longer use. To know what stamp option to select, weigh your window sash. You can then match that exact weight with one of the weight ranges listed alongside each stamp option on the S351-23 product page. Just make sure the nylon fittings match those on the Series 351 before ordering; note that the Series 390 is very similar, but has a bottom nylon shoe with a greater 'depth' or heel-to-toe measurement. Compare both Series with your old hardware to make sure you have the right match.