We exclusively use, and recommend, Muc-Off Innertube Sealant.
Blue Mountain E-bike strongly recommends adding this product to your tires for flat protection. E-bikes go further and can be more difficult to do trailside flat repairs which makes flats even more suckier! Our service is $20 per wheel and includes a 1 year warranty for free labor should you get a flat.
We have NEVER had a bike come back with a flat tire with this product installed!