SWISCO - The Replacement Hardware Authority

Anderson Narrowline Sash Spring

A handy person from Littleton MA says:
The number is either B31 or 331 followed by 1/19 1135. Only other number on it is 11600-17. Assumption is the number is 331 which aligns with one of your replacement sash springs.
User submitted photos of a window balance.
Profile picture of Paul
Paul from SWISCO responded:
Based on your stamp of "331," I recommend our 24-331 Andersen sash balance.
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)