Basic UGRA can be performed solely with a high-frequency linear probe

Advanced UGRA requires high-frequency linear as well as low-frequency curved array probes

Basic UGRA can be performed only with ultrasound without supplemental electrical nerve stimulation (ENS) technique

Advanced UGRA requires a combination of ultrasound and ENS for various blocks

ENS is obsolete for most blocks for the purpose of nerve localisation. However, sometimes peripheral nerves are not visible with ultrasound and ENS can be useful in order to confirm nerve identity

Generally, the main purpose of ENS is a safeguard in order to assist avoiding accidental piercing of peripheral nerves and intraneural injection

Colour Doppler mode can be very useful to identify blood vessels surrounding deeply located target nerves