[Definition] These consist of a radio receiver attached to the collar and a transmitter that the trainer holds. When triggered, the collar delivers an aversive. The specific aversives vary with different makes of collars. Some emit sounds, some vibrate, some release citronella or other aerosol sprays, some apply electrical stimulation. A few collars incorporate several of these. Of these, electrical stimulation is the most common and the most widely used. Early electrical collars provided only a single, high-level shock and were useful only to punish undesirable behavior.[91] Modern electrical collars are adjustable, allowing the trainer to match the stimulation level to the dog's sensitivity and temperament. They deliver a measured level of aversive stimulation that produces significant discomfort and startle without risk of producing permanent physical injury when used correctly.[92] Shock collars are prohibited or restricted in some places.[93][94] [Tool] 
Radio-controlled collars
T r a i n i n g c o l l a r
P r o n g c o l l a r o r p i n c h c o l l a r
R a d i o - c o n t r o l l e d c o l l a r s
M a r t i n g a l e c o l l a r
H e a d c o l l a r
N o - p u l l h a r n e s s
D o g b i t e t u g