Hi there, We are amongst the cheapest on ebay for plastic tubes! Each tube will come with a 16mm flange push cap - making the tube air tight. The tubes are made from high grade polystyrene - which is as clear as glass. The tubes have a round bottom. They are Non-sterile Total volume is 14ml Postage All standard postage is completely free and has been factored into our product pricing PaymentWithin the UK - preferred payment method is PayPalDispatchWe aim to post next working day.We always dispatch to your eBay postal address unless asked to do otherwise.Lost or delayed parcels are totally out of our control.ContactIn the event that there is issue with your order, please message us via the eBay messaging platform prior to leaving negative feedback or marking our 5 stars down.All messages will be answered the same or next working day.Returns and RefundsReturns are accepted in accordance with eBay's 30 day return policy which we have adopted as a Premium Rated Seller.