vivo is technology company which manufactures mobile phones. See below the list of devices that are manufactured by vivo.

By the way, maybe you are looking for vivo user agents?

Mobile phones:

• 1606
• 1610
• V1Max
• V3
• V5
• V5s
• V7
• V7 Plus
• V9
• X21
• X3L
• Y21
• Y21L
• Y28
• Y51
• Y51L
• Y55L
• Y65
• Y66
• Y69
• Y71
• Y81
• Y83