The Firestone® QuickScrubber Kit provides the necessary tools required for the application of QuickPrime Plus Primer. When making a seam between two pieces of liner, it is extremely important to do it right the first time. This kit contains 30 scrub pads and four holders designed specifically for the process of preparing liner for a seam. The scrub pads will help prep the liner while the holders will make the application process simple

The Pond Advisor says....

Then seaming or applying large areas of seam or cover tape this is a great set up for you.  You get four applicators and 30 pads in the seaming kit.  

Enough for multiple jobs or a single large seam.  

Make sure you clean all surfaces from dust, chalk, algae, sludge or scale deposits.  Even new liner needs a quick wash and drying before applying the primer.