How to select the grit size of sandpapers?

Depend on your task and final result , the following are some buying guide which you can refer to:

P40 For removing thick layers of rust and lacquer.
P60 For pre-treating unprocessed surfaces.
P80 For correcting heavy areas of unevenness.
P120 For roughening before priming or pickling.
P180 For initial sanding after priming.
P240 For initial wet sanding after priming.
P400 For smoothing filled surfaces.
P600 For fine sanding before painting.
P1000 For final fine sanding before painting.
P1200 For final fine sanding before painting.
P1500 For final fine sanding before painting.
P2000 For final fine sanding before painting.

What are the sizes available for sanding discs?

CAR-ABRASIVE sanding discs comes with 125mm and 150mm which fit almost all sanders and polishers for autobody work, the abrasive discs are made with different hole pattern, including 8 holes, 15 holes and innovative multi-hole for all brand sanders and deliver excellent dust extraction.

150mm Sanding Discs

125mm Sanding Discs

All abrasive sanding discs

What are the grains of Fastplus sanding discs?

paper sanding discs are ceramic or ceramic alumina grains. The ceramic sanding discs are 30% faster in cutting and more durable than aluminum oxide coated. The ceramic discs can self-sharpen, minimize clogging, and have better performance in heavy-duty sanding for better heat dissipation.
– Gold F15 series sanding discs: ceramic alumina coated
– PURO sanding discs: Ceramic coated
– ROXO abrasive discs: Ceramic coated
– SOFT+ foam sanding and polishing discs: Silicon Carbide grain