This ball is about the size of a standard baseball (maybe just a tad bit smaller...but with use will undoubtedly stretch a little).It's basically a tiny "medicine ball" -- rubber with sand in it (or so it appears).I use it with my 8 yr old for his little league. I can pitch them in the front yard (& we don't have a lot of room) & he usually hits every one (at his skill level & my pitch quality -- and given the weight one pitches from less, much less [depending on one's perspective & desired speed] than half the distance from the pitcher's mound). When hit, they won't go far, maybe 10-20 feet, mostly on the ground (easily used in confined areas & close to the house -- no worry about broken windows, etc.). Feedback is instant; if he hits the ball off-center it travels with a distinct egg shape & the spin is visible so he knows if he hit high or low (usually an indicator he took his eye off the ball). Being heavy, it reinforces a hard swing (many kids swing to hit, but don't swing to hit hard & this helps get them to swing hard--in fact, they're self-motivated to hit these hard).I got six, which was a convenient quantity: At his age (8), fitness & skill (above-average for 8) I will have him hit about three sets of six pitches (6 x 3 = 18 pitches total, usually 15-18 hits; having six balls means shagging three rounds & the break after six pitches to shag & re-position pitcher & batter allows for a suitable rest; kids like to hit these hard but it does tire them a little, so one doesn't want to overdo it).I don't know how long they'll hold up, but a teammate has had some for about a year & those are going strong -- in grass & a typical yard/ball field I'd expect these to last years. Regardless, I'd avoid areas with sharp objects (i.e. don't use near a rose bush as the thorns, for example, could likely pierce the ball's rubber skin & then it would almost certainly tear with use & the sand will spill out; we've had some go into evergreen bushes with the short pickers & they've held up fine).Using mixed balls & bats seems to reinforce overall batting skills -- these with a regular bat (a dozen or two pitches per practice--the kids work hard on these) nicely augments routine baseball practice with pitched & soft-toss baseballs & batting cage practices, swing practice with the long stick with target ball on the end, and, golf-ball sized "wiffle balls" (hollow perforated plastic balls we got from the sporting goods golf dept) with a broomstick/light pipe/other small "bat." This mix has been my approach with my little guy (one or some mix of these maybe ten minutes/day, weather permitting & his mood) & he's almost as good hitting as an eight-year old (birthday within two weeks) kid that's been to seven (!) baseball camps & who plays in two leagues.If your kid really likes baseball & you like to work with him/her, these are a great training aid that will improve some batting skills--more proficiency makes their [and your] enjoyment that much greater (my guy usually really looks forward to wailing on these, but, again, 18 is about his endurance limit, so we do this at the end of batting practices). Yes, they may seem a bit pricey...but six (including shipping) was close to the price to fill up the gas tank; in the scheme of things & his/our love of the game, the price was well worth it!