As a backup battery this is fine, but as already noted, it just doesn't have the life of the Olympus original, and be aware it seems to run out of power with little or no warning - both times it died so quickly I thought the camera had become faulty!
I'd guestimate it has about 1/3 of the Olympus supplied battery-life, maybe less. I can't find the mAh rating of this battery, the original (Olympus BLS-1) seems rated at 1080mAh.
Other than that it's fine - it fits perfectly in the camera, charges in the Olympus charger, and errr.... it comes in a fetching shade of dark grey.......
To be honest I am a tad disappointed and I wish I'd just bought another Olympus BLS-1 battery, but as a back-up, it'll do fine.