Caterpillar 307 OPTION OF IRON OR RUBBER CHAINS (Standard model)
The following are general specifications for the standard Cat 307 mini hydraulic excavator, according to information from Cat.com and Trakindo:

Engine: Cat C2Turbo engine
Net power: 46.8 hp (34.9 kW) at 2,400 rpm
Gross power: 48.9 hp (36.5 kW)
Operating weight (with cab): 15,432 lbs (7,000 kg), which includes the standard stick, counterweight, steel tracks, bucket, and a full fuel tank.
Maximum digging depth: 13.4 ft (4,070 mm)
Maximum reach at ground level: 20.2 ft (6,160 mm)
Maximum dump clearance: 17.1 ft (5,200 mm)
Maximum drawbar pull: 12,792 lbf (56.9 kN)
Travel speeds:
High: 3.2 mph (5.1 km/h)
Low: 2.0 mph (3.2 km/h)
Bucket capacity: 11.7 cubic ft (0.33 cubic meters) with the standard stick

Caterpillar 307E2
The 307E2 is an updated mini hydraulic excavator model. Based on information from Peterson Cat and Cat.com, its specifications include:

Engine: Cat C2.4 Turbo
Net power: 50.3 hp (37.7 kW)
Operating weight (with cab): 16,027 lbs (7,270 kg)
Maximum digging depth: Up to 13.4 ft (4,070 mm) with a standard stick
Hydraulic flow: 40 gpm (154 L/min)

Caterpillar 307.5
The 307.5 is a newer mini excavator model. Its specifications, according to Cat.com, include:

Engine: Cat C2.4 Turbo
Net power: 54.8 hp (40.9 kW)
Gross power: 57.9 hp (43.2 kW)
Displacement: 148 cubic inches (2.43 liters)