There are two types of mouth guards - I would advise the ‘Double layer’ ones for older students (juniors and above) and the ‘Single layer’ ones for younger students.
Mouth guards do not need to be of these type, therefore if you have one from a different activity such as rugby these are fine also.
Sinlge Layer Colours - Black, Blue, Clear, Gold, Green, Pink, Red, Silver or White.
Double Layer Colours - Black, Blue or Red.
Other makes I would advise (though more expensive) are SafeJawz and Shock Doctor. I do not stock these, so these would need to be bought privately. They are easy to find.
Sinlge Layer Mouth Guard £2.50
Double Layer Mouth Guard £4.50