I believe they work the same as a strut bar. They're an aftermarket part that you can install to stiffen up your chassis. They're called 'Front Lower Arm Brace'.

Another member on here bought one from Top Speed Pro 1 here in Dallas and said he could definitely feel a difference after installation. You can search them on eBay. They also carry a strut tower brace for like $50 that wouldn't hurt either. I plan on ordering both of these from them as part of my upcoming suspension modifications.