Nikwax water based waterproofing for leather. Either the liquid or the cream. Has an emulsified wax and a water repellent in it that coats the fibres in the leather. Hasn't softened my saddle after 10000km and it is now pretty well waterproof after repeated applications over time, I can use it in the rain like a plastic saddle. Even better it can be applied if you get your saddle wet, helps it dry out without damage. No animals in it either.