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Relay-Ricoh Engineer's 5500

• Type: Trig Duplex
• Size: 6 Inches / 16 cm
• Material: Bamboo and celluloid
• Scales:
  • Front: DF [ CF CI C ] D L
  • Back: A [ B S T C ] D K

With sewn leather case. No manufacturer's name is given, but the rule is identical to the Relay 550 put out by Scientific Instruments. The spring in the runner is a little loose, but otherwise it's a nice solid little slide rule for pocket or purse.