Region3 Size not setting to part?

Im trying to make a part that will represent where my region is, setting the CFrame and Size. I'm running into a problem where the size is not setting properly. I find it weird because it works just fine for the region2 variable but not the region1.

Is there some kind of restraint on how large a region can be?

local region1 = Region3.new(Vector3.new(3.6, 18.8, 133.2),Vector3.new(30.4, 0.5, 116))
--local region2 = Region3.new(Vector3.new(1,1,1),Vector3.new(10,10,10))

local show = Instance.new("Part")
show.Size = region.Size
show.CFrame = region.CFrame
show.Transparency = 0.5
show.CanCollide = true
show.Anchored = true
show.Parent = workspace

All help is appreciated.