Marantz 12" Refoam Kit
This is the correct kit that fits Marantz HD770, HD880, M10, M16, Model 920 and 940 woofers.
Check for correct dimensions..

Each Refoam Kit includes all the materials needed to repair two (2) woofers:
- Refoaming Instructions
- 2 Foam Surrounds
- Shims For Centering the Voice Coils
- Two 4.124" Inverted (concave) Paper Dust Caps
- 1 Bottle of Specially Formulated Foam Surround Adhesive.

*It can be very difficult to refoam a speaker without removing the dust cap and inserting the plastic shims. The plastic shims are used to center the voice coil and cone assembly while the speaker is being refoamed. If you do not use the plastic shims, the voice coil may be off center and it may lead to the voice coil rubbing.

A - Outside diameter of the surround = 11.5"
B - Roll ends = 10.5"
C - Roll starts / O.D. of the cone = 9.5"
D - Inside diameter of the surround = 9"