Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: Are the water bottles plastic, metal or glass?
Document: This is a beautifully designed product that is highly functional and a wonderful environmental choice. I love sparkling water but always felt a bit guilty about the transport, in glass, across the ocean. Now I no longer have a case of sparkling water taking up room in my cupboard, I no longer have to carry heavy bottles home and I no longer have to schlepp empty bottles to be recycled. I am drinking NYC sparkling water, made as I need it. Fabulous!
We were very surprised at the extraordinary quality of this thing. I snickered when ordering the &#34;Metal Edition&#34;, but the aluminum housing appears to be about an 1/8&#34; thick! It has an impressive, heavy duty chrome plated steel base. Even the plastic parts are substantial and well executed. It is simple to operate and it works every time.
I picked up the Source Metal in white and it looks great. Also performs perfectly. I liked the features of this model and liked its appearance best. But some of the reviews had me concerned. I purchased it any and it has now performed exactly as it should across a half dozen bottles to date.
Would be nice if the added mixes come in bottles that are resealable so you can just use a little. Besides that, the machine makes perfect carbonated water and the level indicator is nice. Design fits really well with any modern kitchen.
Only after buying this was I able to learn it was intended ONLY for carbonating water.This Sodastream is very unlikely to save you money, for the reasons set out below.To operate this, you MUST use Sodastream's proprietary system water bottles. It will not work with other bottles.The kit I bought came with a single bottle. To insure there was a bottle of cold water on hand when the one ran out, I had to buy more.
I've only had the unit for a few days, but it seems to work great. The bottles hold their carbonation better than store bought carbonated beverages. I haven't tried any of the sample flavors that came with it, since I prefer to use organic fruit juices for my flavors.
Bought this for Christmas. My wife lives on colas. I got tired of lugging all the colas bottles up the steps to the house so this seemed like a great way to eliminate that chore. I wasn't sure how my wife would accept this replacement for her colas but she loves it and tells everyone about it. So glad I bought the Sodastream  Source.
You can expect to pay between $10 and $20 to exchange an empty for a full bottle. So having covered the cost of your initial purchase and another $30 to cover the cost of your second CO2 bottle you still have to cover the cost of whatever flavors you have bought from soda stream.150 L  (cost of the kit and 1 spare co2 bottle)of soda stream soft drinks equates to about 12 bottles of the flavor concentrate.
The design of the "source" model is by far the best of any sodastream machine I've seen yet. In terms of ease of use. Way easier and less messy than the kind you screw into place, with this the carbonating bottles just snap into place like they're supposed to. The problem with it is that there's almost no consistency is results. What constitutes as "high fizz" with one batch of soda can be markedly different from the next batch applying the same amount of fizz.
They do not fit. However if you use one of the liter bottles and charge it to a higher degree of carbonation you can then pour off into the smaller bottles and have the benefit of what are supposed to be pressure protecting bottle caps.In costing out how long it may take you to begin to realize a cost savings buying a soda stream system versus buying soft drinks there is another issue. As of now it is fairly easy to get replacement CO2 cartridges repair parts and liter bottles.
Answer: BPA free plastic with metal bottom and cap. The metal bottom is wrapped around the plastic bottle.