No extra expenses This complete kit includes a flashlight and USB cable, perfect for camera testing. Get started right away without any additional expenses. Camera shutter tester (All-in-one kit w/LED Light, w/USB Cable)No extra expenses This product is a simple shutter speed tester for film cameras. By releasing the shutter, the light emitted by the light illuminates the sensor. Shutter speed is measured using this principle. It is possible to measure the shutter speed of various types of film cameras. I recommend that you, do not use any cables other than the USB-A to USB-C Cable included with this product. 
Should you choose to use a power bank, you will probably encounter a smoother testing experience by opting for one equipped with Low Power Mode.

Additional information for focal plane shutter camera users
Is your goal simply to understand the exposure time with the focal plane shutter?
If your purpose for measuring shutter speed is to properly adjust the shutter speed of a focal plane shutter, please consider purchasing another tester that I offer. The tester introduced at the URL below is equipped with two light sensors and can measure the running time of the front curtain and rear curtain. Furthermore, with two optical sensors, it is also possible to know how much exposure bias occurs between the right and left (or top and bottom) of the image plane. Based on this information, you can decide whether to increase (or decrease) the tension of the front curtain or the rear curtain. Information on the shutter tester with two light sensors can be found at the URL below. >>> https://www.ebay.com/itm/155602225328 Contents of this product * Tester unit
* Light source (LED light)
* USB-A to USB-C Cable
Shipping * Expedited International Shipping
* Economy International Shipping Battery Type * Powered by USB-c connector. (This product does not include batteries.) Notes * This product does not include cameras. * This product does not include lights or batteries.
* I recommend that you, do not use any cables other than the USB-A to USB-C Cable included with this product.

Please Note for International Buyers * I ship item from Japan. * Import duties, taxes(example VAT, GST), and charges are not included in the item price or shipping cost. These charges are the buyer's responsibility. * Please check in advance about those additional costs in your customs office before buying. Generally, those additional cost will be charged by the carrier when you receive the item. * I write the customs declaration correctly. No undervalue. No checkmark gift.