If you purchase a new replacement TPU gaiter, it will already have a glue layer applied that you just need to activate when attaching the TPU gaiter to the boot. So in this situation, you do not need to purchase the glue separately.

But if you’re detaching an old TPU gaiter and want to re-attach it, you need to remove the old glue from the parts and apply a new layer of glue to them. This is when you do need to purchase the glue.

How to use the FlexGlue (when re-attaching an old TPU gaiter to a new boot shell):

1. Remove all old glue residue from the TPU gaiter and the boot shell.
2. Apply a thin layer of glue to both parts that will be attached to each other.
3. Let the glue dry for two hours before attaching the parts.
4. Activate the glue by heating it, then press the parts together to join them.
5. Apply pressure to the parts for an hour. You can do this by putting the parts under some suitable weights to ensure a secure bond.