G'day Jason,

Yes, the Delta Light Insul Mugs are stackable, you can stack them with or without the insulated cover on them. You can fit three lids inside one cup, and secure another lid in place, so two insulators and a lid will fit with no worries. They are pretty robust, I use mine fairly regularly, and have had them since 2018, and they're not really showing any signs of wear yet.

G'day Gerard,

These mugs are a perfect fit for the Aeropress Go, so you won't have any troubles at all.

G'day Ian,

Yes, your beloved Mugmate will fit with this mug like a glove! The other really popular option is the X-Brew, but if you've already got a Mugmate I'd stick with that!

G'day Lee,

The Sea to Summit Delta Light Insul Mug is definitely BPA free and made with polypropylene glass composite. These mugs are designed with the insulating sleeve for the purpose to drink hot liquids and will protect your hand from the heat.

G'day JC,

One of my colleagues has done some research on the material used for the Sea to Summit Delta Light Insulated Mug for you. I'll copy and paste what he found for you - It's glass impregnated, similar to fibreglass. In its fine state, the glass fibres are quite flexible, when matted together they provide strength, combined with nylon gives it some flexibility. If they plan on standing on it to pick apples from a tree, it will probably break, if it's in a pack, they will have to work very hard to break it.