Ronald, you can use any EGO batteries on any EGO devices. 7.5 Ah battery will give you more "runtime" but will be a little heavier than the 2.0 or 2.5 Ah battery. Regarding the hedge trimmer replacement blade, here is a "thread" regarding your question for your reference. Bottom line, there is "no replacement" blade - but the "thread" has links to sharpening tools.
https://community.egopowerplus.com/ego/topics/where-do-i-get-replacement-blades-for-my-ego-hedge-tri...
