Here is the bottle:This model is 1L and there is a 750ml version. It’s not clear what the difference is other than the obvious volume… is the head the same and a different silicon section.When not in use it is recommended that the CLEAN side is covered with the cap provided. It is pretty much assumed that everything is dirty.In the everglades it may be necessary to prefilter the water because depending on your water source there can and will be large particulates. In this example I’m using a paper coffee filter and my daughter’s hear band. This method is untested so I do not know how many uses I would get from a single filter. And then there is the weight and disposal requirements. Leave No Trace.I suppose I could have fit it a little better but it was a test fit.Keep in mind this is for those times when there’s just too much junk in the water.