This is NylonX filament by MatterHackers. It comes in half-kilogram spools.
This is a very special filament that can help make stronger parts.
However, it requires special bed preparation, a hardened nozzle, and not all parts can be printed with it.
Do not purchase this without asking us whether your intended application is actually suitable for this filament.
It can be printed briefly with a regular nozzle, but after an hour of printing even our regular nozzle (which is harder than cheap brass nozzles) will wear noticeably.
It may also require drying before using it - Nylon rapidly absorbs water from the air.