This washing up brush is plastic-free and comes with a replaceable head so it will last for absolutely ages. 
 
The brush measures 27cm long and the head is approximately 6cm in diameter and is made from bristle which is degradable.
 
To remove the existing head pull sharply on the metal wires which will disengage it from the handle - a pair of pliers may be helpful - the head will drop out from the wire and the new one can be inserted.