The diameter of the bottleneck opening determines the flow of inside substance. The bottleneck of hour-glass (plate 6A) regulates the flow of sand and time. The flow may be varied by increasing or decreasing the width of the bottleneck. Because of the wider bottleneck (plate 6B) the milk/ lassi (butter-milk) drinking becomes easier. On the other hand the traditional matka, while poring controls the flow of water (plate 6C). The passage of the neck does not allow overflowing from inside (read bottle and jar paradigm). The design of the matka perfectly fits with the waist line (plates 6D&6E) while holding it by arm.

Plate 7A Sprinkler	7B Lawn Sprinkler	7C Water Jet Nozzle	7D Ball Point Pen

(Source:https://www.google.co.in/search?num=10&hl=en&site=imghp&tbm=isch&source=hp&
biw=1312&bih=630&q=How+Bottleneck+works%3F&oq=How+Bottleneck+works%3F&gs_l=im
g.12...4653.23524.0.25662.25.16.1.8.0.1.714.6560.3j1j1j1j3j5j2.16.0...0.0...1ac.1.Z5wNiCwR0z4
#hl=en&site=imghp&tbm=isch&sa=1&q=lawn+sprinkler&oq=Lawn+S&gs_l=img.1.5.0l10.22680
.28581.4.32882.6.6.0.0.0.0.510.1978.0j1j1j2j1j1.6.0...0.0...1c.1.TWda3o7XvA8&pbx=1&bav=on.2
,or.r_gc.r_pw.r_qf.&fp=632a5be22afa9e12&bpcl=35243188&biw=1312&bih=630 ; Oct. 10, 2012)

Sprinklers (plate 7A) force the water with great velocity because the nozzle is designed with bottleneck concept. The water oozes through the passage of the nozzle (plate 7B) reaching the distance because of the bottleneck concept. The water jet nozzles (plate 7C) work with such force because of the bottleneck design concept. Ball Point Pen (plate 7D) applies the same principle to control the flow of ink with the help of spring loaded ball at the tip.