مصبعات الزجاج= tubes, small containers made of PET and ready to blow molding process for making bottles of water and etc.

All plastic soda or "pop" bottles start as a small plastic tube called a preform. When this preform is heated and blown into a bottle shape, it is ready to be filled with your favorite carbonated beverage. ... 25 cc (~0.84 fluid oz). The polymer in our baby soda bottle preforms is polyethylene terephthalate,
https://www.teachersource.com/product/preforms-and-caps

A preform is an intermediate product that is subsequently blown into a polyethylene terephthalate (PET) container. Preforms vary in neck finish, weight, colour and shape, and are specifically designed to meet the needs of customers in different market segments.
https://www.retalgroup.com/products/preforms/

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Note added at 1 hr (2023-11-11 13:25:03 GMT)
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An Egyptian businessman selling injection machine of preforms:
ماكينه حقن سيدل تنتج مصبعات زجاج نفخ وطنيه للاستيراد و التجاره
https://www.youtube.com/watch?app=desktop&v=bsppnWm9wUk&full...

Another video shows how this preforms made into water bottles
مكاينة انتاج علب قوارير الماء أو أي علب مجوفة ( مكينة لانتاج بالنفخ )
https://www.youtube.com/watch?v=qRwDEjuqCGc