16" Adjustable Rod & Bob - 3 sizes to choose. (3 1/2" Bob Size) We offer our customers a choice of brass finish metal pendulums on almost every model pendulum movement we well. These quality, American made adjustable pendulums are available with a choice of 3 different size pendulum bobs (the round disc) 2 1/8" , 2 3/4" and 3 1/2". Please choose your size.