Top Dressing a Lawn
Washed Pit Sand
If you have a particularly fine lawn and use a cylinder mower then this is what you need and this product is used by Bowling and Golf Clubs alike.
Medium/Coarse Bedding Sands
If you have a lawn laid on a very heavy clay and you are trying to improve the drainage, then either of these two will help. The best way to start is to aerate the lawn first (punching hundreds of holes in the surface) and then top dress, letting the coarser sands particles drop into the many holes, thus improving the drainage of the area.