Safety, security, protection and signalling devices; safety, security, protection and signalling devices for use with operating heavy machinery; safety apparatus and instruments; wearable safety and signalling devices; wireless communication devices; wireless communication devices; wearable wireless communication devices; signal transmissions apparatus; radio transmitters and receivers; wireless transmitters and receivers; lanyards for safety, security, protection and signalling devices; lanyards for electronic and wireless devices; a safety and signalling device for use in alerting operators of heavy machinery