Violin bow straight device / straightener in SYDNEY, New South Wales for sale

Good posture is very important when playing violin.
This clever device will help beginners to keep their bow stroke very straight while playing violin.
It is very easy to install. This bow straightener is placed on the f holes parallel to the bridge. This bow straight device is affix to the violin by Velcro straps which can be easily removed when not in use.
It is made of clear plastic which won't obstruct your vision. The pins at the bottom of the bridge should be placed in the f-holes to avoid the bow straightener from moving. The width of the two pins are adjustable to fit different violins.
Various sizes available 4/4, 3/4, 1/2, 1/4 & 1/8.
Note: The violin and bow shown in the photos are for demonstration purposes only and are not included.
This item can be collected from Sydney CBD during office hours or Willoughby in the lower north shore.
I can also send it to anywhere in Australia at postage cost of $2.00.