Grunty 
I received my 3.5Ah EY9201 NiMh 'G' battery for Christmas, so I haven't been able to give it the test of time (hence only 4 stars) but it's a grunty looking battery.It weighs 820g (1lb 13oz) compared with only 700g for the 3Ah 'N' battery; and 520g (1lb 2oz) for the 'C' battery (but then a charge should last 3 times as long as the 'C'). To gain the extra capacity the cells are almost square, giving them a larger cross-sectonal area. This leaves very little space inside the battery pack - hence the screws on the outside.
I've read of the previous NiMh 'N' battery packing up in as little as seventeen months. A friend has had two for nearly two & half years without trouble, but he never lets them run down. If he uses them at work during the day, they go straight onto the charger when he gets home. Maybe that's the secret to long life for NiMh batteries.
The weight and the 55min charging time would be the only negatives.
Buy it without reservations.
After using this battery in my impact driver for six months, I can honestly say I am very glad I bought it. It outlasts the 3.0Ahr NiMH battery that came with the driver by 2X or more and provides impacts that are more powerful. Now I only use the 3.0Ahr battery while the 3.5Ahr power pack is charging. Well worth the extra money.
Restored my drill to better than new performance
I have two panasonic 12v drills - one about 14 years old and one about 8 years old. At the time of purchase they were the finest cordless drills made (see my review) - but time goes on, and other drills have caught up and surpassed the old Panasonics.
A couple of years ago I had the batteries rebuilt at the battery store with NiMh cells. It was disappointing - they never worked like they did before. They wouldn't hold a charge, and didn't seem to have as much power.
I wondered if they weren't really ever as good as I remember. I've moved to Milwaukee V28's as my primary tools.
I bought this battery and charged it up and immediately it brought my drill back to life. This is why I bought the Panasonic in the first place. Great battery.
Just perfect with an exceptional price
I purchased this for my boyfriend -- two as a matter of fact. It's almost the same price as if you had bought one in a retail outlet! I almost get as excited about it as he does. I like the price; he likes the torque! It's a quick charge. He was very happy with them. Who wouldn't have known that this was a great gift? Girls like bling ... boys like tools.
