Mystery items

Hello all,

Along with the Japanese dog tag pictured below, I also dug up two more items.  All found in the hills below Jardine's Lookout, Wong Nai Chong area.  Can anyone enlighten me as to what they are/what they were used for.  Thank you.

Japanese dog tag, by bob

mystery object, by bob

mystery object 2 side 1, by bob

mystery object side 2, by bob