An empty small bag.
An empty small bag which can be filled with 4 stone weight of sand, gravel or chips. Bought on its own as an empty bag.
Blocks
A much bigger block with a cavity/hole going through the center.
Quarry Products
Drainage stone-small smooth rounded stone
Plastering sand
Bags
An empty big bag.
Regular 4" block with a 90 degree offset.
Gravel
Aggregate mix
2" clean medium sized stone
Small empty heavy duty sand bag.