Why use SPLIT KLICK installation washers?
Counter tops have standard size openings for faucets. These holes are much larger than the faucet stems. Faucet stems range from 8mm on single handle faucets to ½-inch and ¾-inch stems on standard 2 handle faucets. When replacing a faucet, it is very difficult crawling under the cabinets and you cannot align the faucet and tighten up (install) the faucet at the same time without an assistant. Without an assistant, many trips under the cabinet are required. With the SPLIT KLICK installation washers, one technician can install and align a faucet in minutes with only one trip under the cabinet.
The alternative is to fill the holes with plumbers putty or silicone to try to hold them in place while you are lying on your back tightening the nut. This requires multiple trips under to the counter to make sure the alignment is correct. The plumbers putty and the silicone will dry later and allow the faucet to eventually move.