Equivalent to a 27C window balance
A home owner from 77020 says:
August 21, 2016
what is the difference between your 28" 390 and 351 Series, i'm replacing window balances on 2 windows
Tom from SWISCO responded:
August 23, 2016
The only difference between those two balances is the size of the shoe. You will need to carefully measure yours to determine the best match. Make sure to account for wear when you do so; your shoe may be slightly smaller than it originally was due to time and use.