Yes, they are compliant. Each vest comes with a pack, inside of which there's an EN 1621-2:2014 certification tag, although that's specifically for the hard back protector they use. The independent testing and certification lab used to certify them has tested them to be within 100mS inflation time (actual tests for the Turtle 2 for example show a tested time of 0.094 seconds, within the CE standard of 100mS for a level 2 protective inflatable device). Why they then don't also have the EN 1621-4 accreditation I'm unsure of but they are endorsed by the police and by IAM who are amongst their users and they've been out for years, proven and reliable in the equestrian world, for which the designs were originally used (and continue to be). The manual one is the one I use as I don't trust any electronic devices to reliably deploy with 100% certainty.
Here's a video showing a police rider walking away from a crash which could have killed him, thanks to his wearing a Helite vest, although there's an obvious question "was this accident avoidable?" as the rider in question failed to anticipate and slow for the hazard of the emerging driver. Whatever his misjudgement, the vest certainly played a part in preventing serious injury or a fatal crash.