Four sizes of solution reservoirs are available to accommodate various sample volumes. All sizes are wide enough for 8 or 12 channel pipettes. The extra large (175ml) reservoirs cut down on frequent refilling and are available with a removable hinged lid to reduce contamination and store solutions without refilling. The large (100ml) size and small (50ml and 25ml) sizes are thin walled polystyrene and are meant to be disposable. The large (175ml) size is thin walled polypropylene and may be subjected to a few autoclavings.