Note: collectors only! Consider these to be museum pieces rather than functional radiological survey meters.  See details in last paragraph.

The CD V-720 model 3 by Landers, Frary & Clark is a high-range radiological survey meter that can discriminate between Beta and Gamma Radiation but only measures Gamma. The range of the CD V-720 model 3 is 0-500 Roentgens per hour. The sliding cover on the bottom of the meter case blocks Beta particles when closed allowing only Gamma radiation to pass through the detector. When the cover is opened this allows Beta particles to pass through the very thin metal membrane on the bottom of the CD V-720’s Ion Chamber resulting in detection of beta radiation.

For those aware of the the CD V720, this is the more obscure one made by Landers, Frary & Clark in the early 60’s.  These became obsolete with the introduction of the Victoreen CD V720 model 3a.  These take two D batteries and one B battery which is extremely expensive to obtain today (22.5 volt) and is why they should be considered collector items.  These have not been tested for proper functioning and are in remarkably good condition.  We have a small quantity of these so the pictures shown may not be the exact unit sold.  Most have various stickers or markings on them but they all are in nice displayable condition with only minor scuff or scratches.  Original instruction manual is NOT included.