This unilateral (single sided) NMR device was initially developed as a way to non-invasively test whether a watermelon was ripe.
Fruit samples can be set on top of the coil for T2 determination which is correlated with sugar content in the fruit. The device is built into a wooden box with dimensions of 18" x 18" x 12". A barrel magnet sits below the rf coil in the center of the box. The sensitive region where NMR experiments can be performed is about 8mm long, axially, centered 17mm above the magnet (to look just inside the rind of the fruit). The magnet has a working field strength of 0.13 T (or Larmor frequency of 5.5 MHz for protons).
In addition to the application of non-invasively measuring sweetness of watermelon, this magnet has been used by the University of California at Davis, Food Science Department for testing whether barrels of tomato sauce have gone rancid.
S. Utsuzawa and E. Fukushima, "Unilateral NMR with a barrel magnet," J. Magn. Reson. 282, 104-113 (2017).
E. Fukushima, Jasper A. Jackson, Unilateral magnet having a remote uniform field region. U.S.Patent No. 6,489,872; December 3, 2002.