Fitbit (NYSE: FIT), the wearables company, has filed a counterclaim to the lawsuit Raleigh sensor technology developer Valencell filed in January. The Valenscell suit alleged that fitbit infringed on four of its patents.

In its response, fitbit denied committing any acts of infringement, questioned the patent claims, and said Valencell so duplicates fitbi technology and its sensors.

Fitbit claims that Valencia infringed its wearable heart rate monitor patent. It says it has been damaged by the Valencell suit and is liable to it “in an amount that adequately compensates fitbit.”

Fitbit also denied Valencel claims that fitbit executives showed an interest in its heart monitor idea as early as 2009, and that executives of the two companies discussed the technology at the consumer electronics show in 2014.

In January Vaslencell also filed a suit against Apple concerning its Apple watch. Apple has not responded at this time