I recently purchased a set of the Hulley Rollers for my kayak - a Wilderness Systems Pungo 140. I must say the rollers make loading and unloading much faster and enjoyable than the old way using the foam blocks. The yak is always centered on the bars. Cuts down the loading time to approx. 10 minutes from start to finish! The only downside is that the whole roller assembly tends to roll on the Yakima mounting bar regardless of how tight you torque the wing nuts down. I remedied the situation by wrapping the bar with black duct tape then placing the roller assembly over the tape. This gives the roller assembly something to "bite" into. No more moving around on the bar! Awesome product. Also great service - had the rollers w/in a couple of days from when the order was placed w/o any special shipping instructions. This is my second time ordering from BackcountryStore.com - I'll definitely be ordering again.