1.SIM card size

There are three types of SIM card  : Mini-SIM[Standard SIM]  , Micro-SIM , and  Nano-SIM .
We are using standard SIM card,length(15mm)*width(12mm). 
Refer to https://en.wikipedia.org/wiki/Subscriber_identity_module#4FF

There are also sim adapters if you don't have sim card of this size .

2.GSM band

WCDMA
HSPA+/UMTS quad-band 850/900/1900/2100MHz
GSM/GPRS quad-band 8
50/900/1900/2100MHz

3.IMEI

Every mobile device has a unique IMEI .
Example: 357784046793822