NailLift clips cannot be used on nails thicker than 1mm as they are designed to fit the average nail, which is about 0.8mm thick, or as thick as a credit card. Clips made any wider will not grip thinner nails.

Many people do have thicker nails, but the grain on standard nail files is often too fine to file the nails down to the appropriate thickness.
We recommend using the Extra-Coarse Nail File provided in every NailLift kit.
The double-sided nail file included in each kit has two different grit numbers. The black side is a coarse 60 grit and will quickly file away the nail surface. The white side is a fine 120 grit for polishing and smoothing.

Front of nail before application.

This illustration shows a side view of how the nail should be filed. As it can be difficult to keep track of filing progress, we suggest following the instructions below.

We recommend first filling in the area to be filed with a permanent marker, as shown in this picture.
Color in the tip of the nail completely from edge to edge. The marking should be about 3mm wide.
You will file away only the top surface of the nail.

It’s important to file the nail as close to the corners as possible, which is why the edge of the nail file is made of a soft, sponge-like material that will not hurt your skin.

This photo shows the nail halfway through the filing process. Once there is only about a 0.5 mm-long stretch of ink left on the front tip of the nail, the clips can be attached.

Nails filed with a 60 grit may feel rough to the touch. The nail can be smoothed down using the white 120 grit side of the nail file if desired.

Before and immediately after attaching NailLift. The NailLift brace has attached nicely, and curve correction is immediately visible.

The picture on the right shows the NailLift brace attached and secured in place with a clear gel pedicure. Gel nail polish remains flexible even after hardening, so it will not interfere with the corrective effects of NailLift.
For thicker nails, the initial correction process can take about a week to complete.