PQ220

amplifier, 20 mm square

PQ25

amplifier, 5 mm diameter

PQ29

amplifier, 9 mm diameter

PQD220

amplifier with sum/difference electronics, 20 mm square

PQD25

amplifier with sum/difference electronics, 5 mm diameter

PQD29

amplifier with sum/difference electronics, 9 mm diameter

Q20

element, 20 mm square

Q5

element, 5 mm diameter

Q9

element, 9 mm diameter