These are placed on the blocks to make an equal 10mm joint between each block both vertically and horizontally, and then the protruding plastic blades are snapped off before grouting.
They also hold the blocks in the correct position next to each other when building a glass block wall.
I have 4 bags of these.
Buy one bag or all 4.
1 bag of 25 is £16
2 bags of 25 is £30
3 bags of 25 is £42
4 bags of 25 is £53
I have retired and clearing out my workshop.
Free Collection from Blackpool or Can Post.