Always use Jack Stands when working underneath your car (never use a single purpose jack) and always use wheel chocks to prevent your car from moving, 2 per wheel is suggested.
Description:
Take safety to the next level and utilise a pair of SCA Wheel Chocks next time you're working under your vehicle. Manufactured from durable red gloss powder coated steel these chocks will make sure your ride stays where you put it. These folding wheel chocks feature a textured rubber pad for improved surface grip and fold flat for easy storage in a tool bag. Small and light enough to chuck in the boot you'll have them at all times just in case you need them.
Good price, thx :)