Seal Rite, the sealant masking system from Everbuild, is a dispenser and micro-fine foil masking tape which achieves a perfectly finished joint every time, says the company.
The dispenser allows the joint width to be adjusted using the outer wheel of the product, with six joint size options ranging from 4mm to 9mm.

The dispenser then runs down one side of the corner joint, nipping off the tape at the bottom, with a built-in blade.

The same is repeated on the adjoining wall to create parallel lines to apply the sealant.