Jack extenders have been around for a long time. What have I (we( been missing all these years? Sort of apples and oranges, but I have three different height extenders for the trolly lift on my four post lift and think nothing about using them. I think twice before using a 4X4 block on my floor jack to get more lift height, but do it on occasion with caution. I would feel a bit more at ease using the pictured extenders than using a block of wood.