Senju Kannon or Sahasrabhuja is the Buddhist statue that can be seen in most Buddhist temples. It is known as the "Thousand-Armed Buddha of Mercy". These 1000 arms represent unlimited mercy. In reality most statues have 42 arms. What is the reason for this difference?
It is believed that missing arms are in other worlds. In Buddhism there are 25 worlds. Senju Kannon has two ordinary arms and 40 extra ones. So, if you multiply 25 with 40 you are going to get exactly 1000, just as it is stated in the name of this statue.
Senju Kannon statue often has 11 heads. They symbolize different aspects of Buddha's personality and his ability to see everything. Senju Kannon is a Bosatsu. It means being an enlightened creature that does not enter Nirvana. It tries to save people from the cycle of birth and death.