The crowdedtablet market now offers a number of devices in various weights, screen sizes and operating systems. But are there any tablets built to withstand tough treatment from kids?

This week, I tested a tablet aimed at ages 4 through 9: the $100 LeapPad Explorer from LeapFrog Enterprises Inc., a company known for its educational children's toys. This tablet, which is available in green or pink, has a built-in microphone, camera, video recorder and kid-size stylus for writing and drawing on its five-inch touch screen (a finger also works).

It was designed with tough plastics, a sheet of Mylar over its glass screen and an extra metal frame around the screen to withstandphysical abuse. This tablet can be used for reading e-books, playing games and running through digital flashcards.

The LeapPad Explorer is the latest in LeapFrog's gadget lineup, which started with the original LeapPad educational toy in the late 1990s and more recently continued with the Leapster Explorer hand-held game in July 2010.

The Explorer tablet for kids works with over 40 downloadable apps and has a topside slot for running older game cartridges. A spokeswoman said the company expects to offer more than 70 apps by the end of this year, and has no plans to stop selling cartridges. Cartridges cost $25 each and downloadable activities -- including games, apps, flash cards, videos and eBooks -- range from $5 to $20 each.

While using the LeapPad Explorer, I discovered plenty of features that would appeal to young kids like fun sounds, on-screen graphics and a sense of accomplishment while progressing through books, games and activities.

The main appeal of the LeapFrog products is the company's focus on personalized education. When children set up the Explorer, they enter their grades, ranging from prekindergarten to sixth grade. The device's activities then automatically tune to a child's capabilities. This means that if a third-grader is performing at a higher level than is expected for that age, the Explorer adjusts to a slightly higher level, and the child is notified and congratulated. However, if a child is progressing at a lower level, the system adjusts to a slightly lower level without notifying the child.

A feature called the LeapFrog Learning Path lets parents digitally track their child's progress. Whenever the Explorer is plugged into a computer, details about the child's time on the device are transferred to the PC so a parent knows how the child is performing and can get tips on how to help the child improve.

The activities address spelling, phonics, math, creativity, science, music and geography. And because of LeapFrog's partnership with Disney-Pixar, kids will likely recognize characters from movies in the Explorer's games and books.

My favorite app was the Ultra eBook, 'Cars 2: Project Undercover.' LeapFrog's ultra eBooks are like eBooks on steroids. They let kids record themselves reading an entire book and play it back. They're animated and have six built-in comprehension activities and three games. They offer stories written at three text levels and they use a visual dictionary for vocabulary development. 'Cars 2: Project Undercover' is the only Ultra eBook currently available, but LeapFrog plans to add six more to its app store before the end of the year.

LeapFrog designed the Explorer tablet with certain features that keep its cost down, and some also solve child-safety concerns. For instance, the Explorer lacks a wireless connection, so kids can't get online without plugging the tablet into a Windows PC or Mac. Downloading apps also requires a parent's password.

Another example is that the LeapPad Explorer runs on four AA batteries rather than the rechargeable lithium ion batteries found in most regular tablets.

LeapFrog's spokeswoman said this keeps the cost low and noted that Li-Ion batteries can leak, making them unsafe for kids' toys. Kids can plug the Explorer into the wall with a $10 AC adapter.

The Explorer is a far cry from popular tablets. The device's one-inch thickness makes it chunkier than most grown-uptablets and its screen is of a lower quality than that of iPads and Android tablets. Its built-in camera has resolution of less than one megapixel. I found the tablet's response time to be a bit sluggish, but doubt most kids under 9 would.

Each Explorer tablet comes loaded with three apps and a free app of choice (eBook, game or video) from the LeapFrog Connect app store, accessible via computer once the tablet is plugged in via USB cord. Preloaded apps include a pet game, which gives kids a pet to care for, Story Studio for creating stories with photos, voice-overs and art, and Art Studio for drawing and painting with various colors and stamped images.

Though the LeapPad Explorer looks a bit chubby compared with regular tablets, its features will be adequate for kids. Its ability to grow over time with more downloaded apps makes it a smart investment for parents.