Plenty of people are digital pack rats and proud of it. And why not? With seemingly unlimited remote storage options available free of charge or for a small monthly fee, they can store their digital photos, videos, music and other files in the cloud without worrying about running out of room.

Personal devices are a different story. Smartphones and tablets with limited amounts of storage can quickly fill up with apps, photos and videos, forcing users to delete content on a regular basis.

This week, I tested a gadget that may relieve some of that local storage burden and could serve as a media-sharing godsend on a long car trip: SanDisk’s $100 Connect Wireless Media Device.

This 2.5-ounce gadget measures about the size of a pad of Post-it Notes and holds 64 gigabytes of photos, videos, music or other files. And here’s where it could come in handy in the car: The SanDisk can be accessed by up to eight devices simultaneously, with five of them streaming high-definition video from it at the same time.

It’s on back order until next week from SanDisk.com and Amazon. A 32-gigabyte version is available for $80 for people who can’t wait. Both versions have SD memory card slots for expanding their storage.

Several companies have created gadgets that do similar things, including Seagate and Kingston. I found SanDisk’s Wireless Media Device to be a simple solution for quickly transferring data off of a phone or tablet. It also was lightweight and portable and worked well for sharing content to many devices in the same room at once.

The SanDisk device works with a free app that can be downloaded from Apple’s App Store, the Android operating system’s Google Play store or Amazon’s Appstore for Kindle Fire. I successfully tested it on the iPhone, iPad and a Moto X smartphone running Android, streaming high-definition video to the three devices at once without a problem. And I tapped one button to open options for offloading photos from my smartphone to the SanDisk.

In addition to the transfer apps, the SanDisk device has a USB cord that enables transfers to or from a Mac or Windows PC.

As for video playback, you still have to worry about file formats that won’t play on some devices. The iOS app won’t play .AVI or .WMV files, since these are formats created by Windows machines, and Android won’t play .MOV files, which are in Apple’s QuickTime format.

While file transfers from the SanDisk are easy, the process for moving files to it is a little clunky, involving the drag-and-drop method.

One of the most attractive features of this device is that it doesn’t require an Internet connection to stream its content to other devices.

It shows up in a device’s Wi-Fi settings as its own network, and you select it from your device to connect to the SanDisk. This means you can toss it in your bag for a long road trip and let many people access its content at the same time. SanDisk promises it will work from up to 150 feet away, and it did in my house.

You can opt to connect the SanDisk to your Wi-Fi network, which might come in handy in certain circumstances. For example, after I transferred over a dozen Word documents to the SanDisk device from my Mac via USB cord, I opened and read these documents on my iPad with several cloud-based apps, including Microsoft’s Office Mobile and SkyDrive apps, Evernote and Google Drive, without having to connect to the Internet.

The SanDisk takes three hours to fully charge, which it can do via USB from a computer or by using its power adapter. One charge lasts for up to eight hours of continuous streaming. In my mixed-use tests, the battery lasted for well over eight hours. It also has a smart battery feature that turns off the device if it hasn’t been used in 10 minutes.

A single black button on the front edge of the SanDisk turns it on, and three tiny icons glow to represent the battery indicator, the drive broadcasting its Wi-Fi signal and whether or not the drive is also connected to the Internet via your local Wi-Fi network.

As is often the case, this gadget’s corresponding iOS and Android apps looked slightly different and didn’t operate exactly the same way. But both apps use an icon with up and down arrows to represent the way content can be transferred wirelessly to or from a mobile device. Tap this and select content to upload to the SanDisk from your device or to your device from the SanDisk.

The apps’ transfer button moves content to and from your SanDisk and pulls up a Share option, which makes it simple to share digital files with friends via email, Facebook or Picasa — or to copy the files. To use this feature, the SanDisk must be connected to the Internet via Wi-Fi. Photos can be edited and re-saved within the SanDisk app, and several can be played at once using a slide-show option.

My husband and I each have different accounts for storing photos and videos. He downloaded the SanDisk app to his iPhone and easily uploaded a bunch of his photos onto my SanDisk device. Once images were there, I could download the photos onto my Android phone or iPad using the app, or simply look at them. But two attempts to transfer an eight-minute video from my husband’s iPhone failed after a few minutes of waiting.

A SanDisk representative said this may have been caused by the phone going to “sleep,” which stopped the video transfer. The company plans an app update to fix this in coming weeks.

If your mobile device is getting crowded, or if you want a better way to stream content to nearby friends without the hassle of emailing or texting huge files, the SanDisk Connect Wireless Media Device is a smart solution.

Write to Katie at katie.boehret@wsj.com.