From left to right I have three generations of battery monitor represented. The original Link 10 was manufactured by Cruising Equipment Company and they really started a good thing. Despite many of the "LINK" products tending to be a little buggy they were generally well regarded and loved by boaters.
Somewhere along the way Cruising Equipment became Heart Interface and then Xantrex bought Heart Interface.
Xantrex then found TBS Electronics in the Netherlands and began importing and re-branding the TBS made monitor as the Xantrex XBM (pictured in the middle). The XBM was the identical monitor to the Victron 501 and was a very, very reliable device. It also offered a computer interface option something new to battery monitors at the time.
Eventually Xantrex made the switch to all TBS built battery monitors such as the current Link-Lite and Link-Pro. They have proven to be solid though very expensive units.
About the time Xantrex signed on to re-label the TBS monitors Victron found a new manufacturer to build their units, though I don't know who it is. The Victron BMV-602S is pictured on the right and bears little resemblance to the TBS built monitors.