The best product to use to preserve leather and to produce a nice sheen is Connolly Hide Food. Not only do I use it for my holsters, but also on my shoes and leather furniture - great stuff!
For many years, I was using Pecard but after witnessing the results of Hide Food I have made a permanent change. You can find the product at the the following auto store:
Beverly Hills Motorsport
Superior Car Care
Auto Geek
If you do a search for 'Connolly Hide Care' on Google, you will get additional results.
I hope his information is useful to you.
Best of luck,
Albert