The other room is the same style except longer. The stamp however reads 33ds ea 42 as per attached picture.
It wofactappear I need the 351 series 34" per this page: 33-Series-351-Balance/pd/Series-351-Channel-Balances/S351-34 however mine are in fact double spring as the ds seems to imply.
Would I opt for the 3340 or 3350 depending on weight then? Its a pretty large window.

