G'day Neryl,

The Sea to Summit S.I Seat Deluxe will definately add some extra padding, however I cant advise on how it would effect your sciatica.  Its designed to give abit of extra comfort when out hiking and with use on other hard surfaces like benches, etc.  How it would feel on an already 'padded' surface may vary.

Hi Christine,

This is a really good question. I couldn't try and fit the S.I Seat Deluxe into the Air Chair myself as we don't have any stock at the moment, so I called Sea To Summit. It turns out it's not something they had considered either, so they are going to try this and get back to me but this probably won't be until tomorrow.

My feelings, which were shared with the Sea To Summit representative I spoke to, are that Sea To Summit SI Seat Deluxe will be too thin to be effective in the Sea To Summit Air Chair, it requires the bulk of the mats to fill it out and create some structure. I'll post my findings back here once STS get back in touch.

Sorry I couldn't give you an answer straight away.

I don't have experience with either of those mats Christine, and I'm still waiting to hear back from STS regarding the SI Seat Deluxe sorry.

The best advice I can give here regarding how your mats will work with the Air Chair is to compare the sizes of your mat/s with the dimensions of the Sea To Summit mats. All the Sea To Summit mats fit the Air Chair (except the S.I. Comfort Deluxe model), so if any of your mats are close in dimensions, which they are likely to be, then there's a pretty safe bet that they will fit. 

Keep in mind that there are two sizes of Air Chair, you are most likely going to find that the regular size will be most suitable for your lightweight mats.

G'day Christine,

I've heard back from Sea to Summit about it now and they've said that it won't work. Unfortunately, it's just not thick enough to suit the air chair.