Shaped for the shoe and the load.

Your orthotics are shaped from an impression of your own feet, not a size chart, and the shell is set to your weight band. We confirm the length from the impression and trim the pair to the shoe type you told us about. If anything is off, a remake is free inside the 180-day guarantee.

A shelf insole is one of three or four shapes chosen to fit millions of feet; it cushions but it cannot hold a heel or contour an arch that isn't its own. A custom orthotic is shaped from an impression of your foot, so the heel cup, arch profile and forefoot relief are yours. If a shelf insole has already solved your problem, keep it — we say so in our guides.

Full-length designs fit sneakers, walking and running shoes, work boots and most lace-ups; remove the shoe's own insole and slide ours in, trimming along the guide if needed. The three-quarter design is for dress shoes and flats where there is no room for a full insole. Each pair is shaped for one shoe type, which is why a second pair for a different shoe is $139.

No — that is exactly what an impression is for. Each orthotic is made from its own footprint, so a half-size difference, a flatter left arch or a wider right forefoot is built in. Order the size of your larger foot and note the difference in the order comments if you like.

The shell typically outlasts several pairs of shoes; the top cover wears first and can be replaced. If your weight, activity or footwear changes a lot, the design may need updating — that is a reorder from your impression on file, not a new kit.