Letters in power tool model have different meanings. You must understand them in order to choose right tool.
The first letter indicates category of tool
G=Professional (GBH2-22RE)
P = household grade (PBS75A)
A=garden tools (ART30Combitrim)
The second and third letters indicate type of machine
BM=electric drill (GBM350RE)
SB=Impact Drill (GSB13RE)
BH=electric hammer (GBH2-22RE)
SH=electrocleaner (GSH388X)
SR= Cordless screwdriver (GSR9.6-2)
WS=angle grinder (GWS7-125)
ST=curve saw (GST65E)
HO=electric planer (GHO10-82)
HG=hot air dryer (GHG500-2)
DM=marble machine (GDM13-34)

The number after fourth digit indicates main parameters of machine
Kilogram level (GBH2-22S)
Power (GBM350RE)
Maximum turning diameter (GBH2-26RE)
Mechanical multi-gear speed control (GBM13-2RE)
Voltage (charger) (GSR9.6-1)
Sawing capability (GST54E)
Disc diameter (GWS14-150CI)
The suffix letter can indicate individual function of this machine:
R=forward and backward (GSB550RE)
E=Electronic Variable Speed (GSB550RE)
A=vacuum function (GSS280A)
P=Rotate function (GST85PBE)
B=curved handle (GWS24-180B)
V=voltage (charger) (GSR7.2V)
C=Constant Speed Control (GWS8-100CE)
L=Long arm straight grinder (GGS27L)
S=flat drilling function (GBH2-24DSR)
D=notch function (GBH5-38D)
F=Change collet (GBH4DFE)
X=Hexagonal drill/chisel (GBH5-38X)

Please note following when using:
1. Hand-held power tools (class II power tools). It is necessary to provide 220V mains power as an energy drive, do not connect to 380V industrial mains, otherwise machine's motor will be damaged.
2. When using power tools, basic safety protection is required. Protective equipment includes: goggles, hard hats, masks (gas masks), ear plugs, gloves (wire gloves are not allowed for rotating tools), protective clothing, insulating shoes, etc. And before using tool, read product manual or use it under guidance of a qualified worker. Unless otherwise noted, power tools require two hands to operate.
3. Hand-held power tools (class II power tools) have double insulation protection, i.e. basic insulation and reinforced insulation, which are designated by word "back". During operation, it is important to keep power cord intact, otherwise there is a risk of leakage. Do not use in wet, underwater, flammable and explosive areas.
4. Power tools use series motors as motors, which are composed of rotors, stators and carbon brushes. If overloaded, motor can easily burn out.
5. Cordless power tools are mainly divided into two types: nickel-cadmium battery charging tools and lithium-ion battery charging tools. Among them, lithium-ion batteries have advantages of no memory effect, small size, and almost no self-discharge, which is trend of future rechargeable tools.
6. Measuring tools are divided into: range finder, wall detector, laser level, digital angle ruler, etc. Among them, laser part uses a class II safety laser with a wavelength of 635 nanometers and red color.