An aqua 5 Newton (510 gm) classic spring scale with a sturdy acrylic tube that protects the spring. We've found the tube reduces damage to the spring in classroom situations.
The convenient, easy to read results are shown in both Newtons and grams.
As an added feature the zero adjust is a cinch to use. You just turn screw on the top cap.
Dimensions: 10" full length, 1" diameter transparent acrylic tube.