My original battery from my 87V still hasn't run flat, despite a (relatively) LOT of use, it just keeps on and on going! But when it eventually runs low I'm going to replace it with one of these lithium 9V batteries.
According to the spec sheet, the lithium battery has about 750mAh at low discharge rates, such as in the 87V, compared to about 600mAh from the standard Energizer 9V Alkaline.
I just hate using Alkaline batteries or cells in anything, particularly valuable devices like the 87V, or my flashlights.
But they are nearly four times the price of the standard Energizer 9V's...