Transparent, square shape polyethylene terephthalate copolyester (PET) bottles from Thermo Scientific Nalgene®. Narrow neck, with moulded-in handgrips for easier pouring and high density polyethylene leakproof screw closure. An inexpensive alternative to glass for storage of media. Bottles and closures are non-pyrogenic and supplied radiation sterilised. Packed in shrink-wrapped trays within an outer pack.