G'day Bea,

The biggest difference is that the Pack Liners are larger in size and do not come with the carry straps.  They are designed to be inserted inside of your pack to ensure the contents stays dry.  The Dry Bags are smaller in capacity - 10L and 20L and are designed for (but not limited to) keeping essentials dry while slung over your shoulder on your day trip adventure.  The waterproofing and closure of both are the same.  Hope that helps :)

G'day Bea,

Thanks for your enquiry. The best pack liner for your 65L pack would be the medium size as its capacity is up to 70L. 

G'day Lou,

The Sea to Summit Pack Liner we have is made from a 70 denier polyurethane coated nylon material, whereas the Ultra-sil version is made from a 30 denier Ultra-sil (an ultralight siliconised Cordura) fabric. Apart from this the base line shape and size are the same across the models.

G'day Louise,

The Sea to Summit Pack Liner can work as a stand-alone dry bag, however we do sell the Sea to Summit Big River Dry Sack in the 65L might be a more durable and easier to attach option.

G'day Lachlan,

The Small Sea to Summit Pack Liner has a 50L capacity, the medium has a 70L capacity and the large has a 90L capacity. 

G'day Steph,

I'd recommend you go for the Medium Sea to Summit Pack Liner for your 65L bag. The Medium Liner has a 70L capacity, so will fit nicely in your bag. 

G'day Amanda,

It would be absolutely possible. Many people use multiple dry bags throughout their pack to separate their gear (I use about 7 different dry sacks). The great thing about them is you just roll the top down as far as needed.

G'day Josh,

I'd recommend going with the medium sized Sea to Summit Pack Liner which can hold up to 70L. You can then roll the top down as required. The small sized liner is only 50L meaning you'll loose potential space in your pack.