[4 lb] I purchased 5 of these for my light stands as well as my video backdrop stands and having had back surgery several months ago it's the thing that still allows me to work in my studio since I couldn't lift any of those stands. I don't use them for tracks so those are not useful to me but game changing for the stands as I frequently have to reconfigure the studio for different use cases. Well worth the money.

[51.5 x 3 x 1.5"] Awhile ago, I purchased the ProAm USA SolidTrax Universal Track Dolly and was a bit disappointed at its engineering. It was slightly flimsy, did not roll smoothly and the tripod seemed to torque a bit when slid along teh tracks. This is not a personal attack on Proam as I am sure the company founders are great folks. I own their ProAm USA SolidTrax Universal Platform Dolly and like it okay. The Proam dollies are not as good as the Glide Gear system on a few levels. Firstly, the Glide Gear dolly arms are stronger than the Proam and the tripod does not torque. The Glide Gear tripod dolly stays on the tracks and does not jump track like the Proam and you can adjust the Glide Gear arms to different lengths if you want to use different tracks. Plus, Glide Gear gives you caster wheels for smooth floor use if needed. The Glide Gear wheels are smoother rolling right out of the box and I did not have to adjust their tension. I am happy with my purchase.

[Round] I use it for any music videos I shoot. The three wheel or one wheel option is great! The 3 weeks grip the track marvelously!

[51.5 x 3 x 1.5"] I am using this dolly with the track wheels on 1 inch conduit piping. I'm actually putting a 6 foot crane on top of my tripod and it still runs perfectly smooth! The only complaint I have is similar to others. The supplied bag is really nice but it doesn't fit the dolly if the track wheels are attached. There is no way I'm taking off the track wheels every time I use it just so it fits. So it mainly just gets folded up and carried around as is. But that being said its pretty sturdy, i'm not worried about it being damaged when moving it around. I'm using it with: Ravelli AVT Professional 67 The tripod fits great.

[51.5 x 3 x 1.5"] I am using the dolly along with the Glide Gear track for shooting artwork with a prime lens. Together with the track this is a perfect solution for moving the camera closer and further away from subject. The wheel system is solid and smooth. Very easy to change the wheels and all tools are included. Could not ask for more.

[Round] It is a good small compact dolly and works well on tracks or PVC pipe.

[Straight] Item came very fast. I like the fact there are two sets of wheels so I can either roll along a smooth surface or use the other wheels to roll along pipes on a not so smooth ground. Only negative was box showed a tool to use with it which was not in the box and no pamphlet inside with contact info or changing wheels and a few other things. Not a game changer but disappointed int an otherwise superior product.

[Round] I was hesitant about this rig, but it's super reliable, sable and easy to change the wheels out. everything needed is included.

[Aluminum] Good - easily fit my tripod. Runs smoothly on the Cinetrac rubber track.