The VS-510P Wireless TTL Shoe Mount Flash from Bolt is a dedicated flash for use with Pentax & Samsung DSLR cameras. The VS-510 features a guide number of 141" at ISO 100 and an adjustable tilt head with five positions: 0 to 90°. You can also twist it to the left up to 120° and to the right up to 180°. It covers a 24-105mm range (in 35mm full frame format) and also offers rear curtain synchronization for shooting at slower shutter speeds. The included mount allows you to attach it to any 1/4"-20 screw for flat surfaces, tripods or stands. The VS-510 has an autofocus assist for low-light photography, and an automatic power-saving function that turns the flash off when it"s inactive. It is powered by four AA batteries (not included), with a flash duration between 1/1000 and 1/20,000 of a second. Mount: Shoe Guide No.: 141.08" (43 m) ISO100 at 50 mm position Exposure Control: Manual/TTL TTL Dedication: Yes Bounce Head: Yes, +0° to +90° Swivel Head: Yes, 180° Coverage: 35 mm (Full frame) Zoom Head: Full frame: 24 mm - 105 mm Off Camera Terminal: None Recycle Time: Approximately 0.5 seconds - 9.0 seconds Flash-ready Indicator: Yes Compensation: Not Specified By Manufacturer Wireless Communication Channels: 4 Channels Wireless Groups: 3 Groups Power Source: 4x AA Alkaline, Lithium, Rechargeable Ni-MH Batteries Dimensions (WxHxD): 2.6 x 3.9 x 4.7" / 6.5 x 10 x 12 cm Weight: 9.17 oz / 260 g Without batteries