Police are appealing for witnesses after a 16-year-old boy was robbed as he cycled in Clifton Road, Worthing, on Friday 15 June at 10.50pm.
Two men blocked his way and demanded he hand over his mobile phone.
When he resisted, they threatened to hit him. They took his Iphone and the victim rode off.
The first suspect is described as a white man, aged in his early 20s, 5ft 9in of slim build with shaven blonde hair.
He had between two and four teeth missing from the top of his mouth. He was wearing a grey hooded top.
The second suspect is described as a white man, aged early 20s, 5ft 11in of slim build and with brown hair, gelled on the top and closely cropped on the sides. He was wearing a black waterproof type jacket.
Anyone who witnessed the incident is asked to call 101 quoting serial 1861 of 15/6.
Alternatively, call the independent charity Crimestoppers anonymously on 0800 555 111.