Pumice 100 gr. extra fine
Pumice 100 gr. extra fine - 6/0
Pumice 100 gr. extra fine - 6/0 to fill the grain of the wood.
You can fill the grain by taking some pumice and spray it out on a piece of paper (not directly on the guitar). Then moisten your rubbing pad with alcohol and take some pumice from the paper. Firmly press your rubbing pad on the wood and make small circles to sand the wood with the pumice. The pad is taking the wood dust and rubbing it into the pores of the wood. If the pores look white, you have used to much pumice.
The goal is to sand the wood using the pumice and rubbing the wood dust into the pores.