Is there a particular model of sled that is approved for use during the new Army Combat Fitness Test (ACFT, formerly the ACRT)?

I've been thinking about adding a weight sled to my home gym to use for general conditioning, but I figure I might as well get something that can help me prep for the ACFT when it is rolled out Army wide in the next couple of years. After a quick web search I've seen endless configurations. Some use a runner system, like an ice sled, while others just have a flat base. It's been a been a while since my physics class, but I imagine the runner style move easier with the same amount of weight because of surface area in contact with ground, friction, etc. I'm assuming there will be some type of standardization across the Army. The sled in the pics I've seen, as well as the ACFT set-up my unit bought, look similar to the one pictured below. Has anyone seen anything official about what type of sled will be utilized? Thus far my searches have come up empty.