One side says 7.5 the other size 10.0

Hello,

Your photos resemble the 15-251 Inverted Single Support. This system uses Series 160 Coil Balances sold separately. We do offer the S160-10 and S160-7 but note that the same coils should be used on both sides to ensure that the sash is evenly supported. I would recommend weighing your sash to confirm the correct strength options. Also, see the 16-032 Mounting Clips. Thank you! 

Measurements of 15-251

Dimensions for 16-032