20 10" High Density Anti-Static Poly-Inner Vinyl Record Sleeves
HDPE POLYETHYLENE sleeves have major advantages over paper inner ones as paper can mark the vinyl. Also open centre holes allow dust to enter.
As for the poly inner itself you need to ensure that its not PVC which is produced with artificial softeners, sleeves which have softeners and can leach onto the vinyl,
HDPE have an anti-static additive which prevents the sleeve form sticking to the vinyl