For classroom and groups, we suggest our Wired LED Assortments that are meant for long-term use. They are easier to use for young users and the terminals do not break.
Notes:
LEDs have polarity which means that the longer leg needs to go to the red battery packs side.
Never connect and LED directly to the battery holder – they will break.
LEDs are a consumable when used with Squishy Circuits – the terminals will break and erode during use. Expect a few hours of use before replacement is required.