Which week to introduce play gym

My girl started using her play gym around 6 to 8 weeks, when she could finally track moving objects a bit and was awake for longer stretches. Honestly the first few sessions she just lay there looking blur, so don't expect too much reaction right away lah. It only got more fun around 3 months when she started batting at the hanging toys on purpose. Just make sure you are always nearby since young babies tire out faster than you'd think on their backs.