I just picked up a CORE "gasless" 18volt lithium-ion powered string trimmer last week. I got it for a song from the Woot.com daily deal site. If I'd known what I know now, I'd bought more. The deal only lasted for a day, but aside from my John Deere lawn tractor, this is the best purchase I've ever made in outdoor power equipment. I'm kicking myself that I could have had an extra power head, battery and charger for $80 bucks and I fooled around and missed it. But I did get one. And I'm glad I did. I've posted a few videos below. My home sits on a sloped 1.25 acre lot with a rocky, privet invested, stormwater drainage swale running through the back yard. I've been on the lookout for a brush cutter weed wacker to help me maintain the rapid growth of privet and weeds here. I'm pretty impressed with the performance of this trimmer. You can check out the technology of the space age motor design on the CORE power website. They've been bought out by MTD and these motors are now powering TroyBilt and Cub Cadet's line of cordless OPE. In the video below, I'm using the standard bump head that comes with the trimmer (not the Grass Gator Bladed head). It's outfitted with .095 and does a pretty good job. You can get a sense of the torque as it just slices through the heavy brush with ease. Sorry for the video quality. I'm holding my phone in one hand and the trimmer in the other. Luckily it only weighs about 10 pounds! In the next video, I've swapped out the standard bump head for a Grass Gator Extra Heavy Duty metal bladed head. I was a bit hesitant to do much with this since we are talking about an 18 volt machine (I've since learned that voltage isn't everything). But the CORE Power folks claim that this motor supplies 25% more torque than a 25cc engine. So I decided to give it a go. I've seen other cordless brushcutters outfitted with metal blades, so that gave me some confidence that the CORE motor was up to the task. I was hesitant at first, and just spun it a few times to get a feel for how the trimmer was handling the big metal bladed head. But it just seemed to take to it like it was made for it. Effortlessly spinning this monster blade up to 7000 rpms in a split second. You can hear a couple times I bumped into large privet stumps (5-8 inches across) that I had cut down early Spring of this year with a chain saw. The head bumps away but it doesn't stop the motor. Thankfully, the unique pivot blade design of the GG brush cutter head saves me more than a few times as I bump into these hidden monster privet stumps. Gotta get some more glyphosate!