Not knowing what size your child is..........
Teknetics/First Texas used to make the Digitek.
Nokta Makro has a new kids detector too.
The Minelab Vanquish 340, 440 or 540 using the 8"or 10" coil is very lightweight and has telescoping shafts. You can even remove the telescoping shaft from the arm cuff and run the main shaft all the way through the control housing and re-attach the arm cuff to the main shaft. It shortens it a lot and makes it a straight shaft child sized detector.