Why is this unit more than twice the price of the "acelete auto-start 2.0 power ball wrist trainer ..." ?

I can attest to that. My NSD powerball lasted four and a half years. With the same amount of use, my Acelete lasted only a month and a half.

noise level ? can I use this at a silent environment like office ?

Yes. Our surgeons use them in their offices while on the phone. It makes very little noise. Sort of a brushing sound.

does it have led light ?

No, all NSD Spinners with ergonomic/rubber band in black are not equipped with LED lights. However, the Speedometer on the top goes with self-powered back LED light when you spin and reach 3,000 RPM.

What is the difference between the nsd power and nsd titan? the price is as twice as big for titan

Their Material and Size are different. PB-688 series Spinner are made of military-grade plastic while PB-888 Titan series are made of zinc rotor and Aluminum Alloy shell. PB-688 is a tennis ball sized Spinner while PB-888 is as big as a softball.

Color	Black
Size	5 x 3 x 4.50"
Style	Without Digital LCD Counter
League	LPGA
Height	4.5 inches
Item display length	5 inches
Weight	2.27 kg
Item display width	3 inches
Shape	Oval
Material type	Plastic
Seasons	Spring/Summer
Sport	Airsoft, Basketball, Boating, Bowling, Cycling, Golf, Hunting, Martial Arts, Tennis
Included components	Plastic shells, Stainless steal axle, Zinc rotor
Batteries included?	No
Brand	NSD
Department	Unisex
Manufacturer	NSD Power
Item model number	PB-688A Black
Product Dimensions	12.7 x 6.5 x 0.1 cm; 252 g
ASIN	B007MEWU14

Power AutoStart Spinner Gyroscopic Wrist and Forearm Exerciser with Auto Start Feature

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