Style 7500 is a 9.6 oz/sq yd boat and tooling type fiberglass cloth. 7500 uses the ECG 37 1/2 yarn in the warp and fill. The "G" filament used in 7500 being just 9 microns, versus the much larger cheaper-to-make 13 micron "K" filament used in style 1800 of the same weight and thread count, makes for a very flexible cloth. The two major finishes we have available of the style 7500 is the universal silane 627 from BGF and their 504 Volan. The 627 is on most of the tape rolls also. Volan, especially BGF's superb 504 Volan, is the softest of all finishes we sell. Here's a video showing how the finish effects the handling of any particular style of fiberlass fabric