Both the Ro-5 and Ro-9 were especially designed to be used in the PT-Mi-K metallic antitank mine.
They are similar in operation and design features except that the Ro-9 has an integral booster charge, while the Ro-5 requires a separate booster charge to be placed in the mine.
Both fuzes are equipped with shearpin retained strikers.
Pressure on the head of the striker releases the shearpin and frees the striker to actuate the detonator.
Length: 70mm , diameter: 50mm.