"Checked in shop and it seemed reasonably accurate both horizontal and vertical. Cheap construction so I would advise checking that it is suitable for your needs when you pick it up (I doubt that they are all accurate and you may get a bad one). Have used it on scaffolding and it worked fine, magnets held it in place. Manufacturer might consider putting a v groove in the base to help get it straight on a pipe."
"Works as well as my £30 stabilla. Got this as a backup for my site bag and think its worth every penny. Only downside is the plastic around the bubbles could be better quality as one is chipped after the first day"