I wouldn't touch them with a 10ft disinfected bargepole, and I'll tell you why
Has the kit been proven to work by a national regulator - No. How do I know - the website would be covered with the certification and it isn't- so forget it
With any piece of kit, you need to practise how to use it regularly. Would you do this ?
For the kit to be of any use it would need to be with your child every time he or she eats or drinks. Can you guarantee this would happen ?
If you really are that anxious there are sensible things you can do -
paediatric first aid courses - cover all sorts of childhood incidents, how to spot them and what to do.
sit with your child when they are eating
encourage your child to chew properly
avoid TV / films when they are eating so they can focus on the eating and not laugh and thus inhale food
Please don't waste your money on this