Small Sun:
I actually found the plastic container when i when to buy the e-ballast for my diy 27W PL tube. Address:
得利五金超級市場
地址:觀塘駿業街66號巧運工業大廈A2-D地下
Actually they come in different sizes, I just bought one that i think can fit in the bioballs. I think they are used for putting pills (medicine) or collecting urine sample for hospital
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Originally i thought of buying the plastic tube from fish street and cut them into the right length, but can't find the right size.
This plastic container is just right. I think u can find them in many places. Maybe the drug store, pharmacy in Po Lam(?? )