Opel Laubfrosch
| Opel 4/12 HP | |
| Engine | In-line four-cylinder |
| Displacement | 951 cm³ |
| Bore * stroke | 58 * 90 mm |
| Compression | 7,0 : 1 |
| Crankshaft | Double mounted |
| Engine control | SV |
| Mixture preparation | Carburetor |
| Power | 9 kW (12 HP) |
| Nominal rotation speed | 2200 rpm |
| Power drive design | Front engine with rear-wheel drive |
| Transmission | Three-speed, sliding gear |
| Suspension f/r | Rigid axle, leaf springs, quarter elliptical |
| Foot brake | Rear wheels, mechanical |
| Handbrake | Transmission |
| Electrics | 12 V |
| Length | 3140 mm |
| Width | 1340 mm |
| Height | 1650 mm |
| Weight | 570 kg + driver |
| Maximum speed | Approx. 70 km/h |
| Price | Approx. 4600 Rentenmark, 2500 RM |
| Construction period | 1924 - 1926 |
| Version | Four seater since 1925 |
With this copy of the Citroen 5 CV as the only model Opel rises to a series producer and Germany receives (after the USA and France) for the first time an automobile assembly line production. At a time when the vehicles still changed a lot with basics, in any case is stolen a lot. Usually at or after the takeover however also developed significantly. For this Opel initially it is not the time. One has built a new factory and invested much money, which will first of all be generated.
At least the color is changed over from Citroen yellow to Opel green, what brings the 4/12 the name tree frog. Except in ignition, cooling and bore both cars are so similiar, despite slightly different measures, Citroen even goes to trial. Finally however, the tree frog from Opel is yet further developed and repealed as a copy. During this time, Citroen is one of the largest manufacturers in Europe, Opel's successes come later. 07/06