An empty big bag.
An empty big bag which can hold a tonne 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.
Regular 4" block with a 90 degree offset.
Gravel
Clause 804
Chips
3/8" Chips. Very small stones
Quarry Products
Plastering sand
2" clean medium sized stone
Aggregate mix
Regular 4" block with a 30 degree offset.