An adjustable holder configured to support a fluid dispensing container. The adjustable holder may include a clamp portion and a locking assembly. The clamp portion may include a first part and a second part, with the second part being movable relative to the first part. The first and second parts may include first and second locking channels. The locking assembly may include a connection member that is located within the first and second locking channels and a locking member. The locking member may be alterable between a locked state and an unlocked state, such that the first part of the clamp is movable relative to the second part of the clamp portion when the locking member is in the unlocked state. The first part may be movable relative to the second part between an open state and a closed state.