This tee was produced somewhere around 1990 under the name "Floating Tee".... This one consist of an arm that slides onto any tee and is held in place by the opposite forces exerted at the two points where the arm connects to the grounded tee. The arm is made out of hard but flexible plastic. When a ball is teed up on the arm, the arm flexes down and levels out some.
The grounded black tee is modern. The levered green arm is 30 years or so of age. While not particularly old, it is quite the visual rarity today.