Plain timer is a plain, simple timer for iPad/iPhone/iPod Touch (only for iOS4.0 or later), that can me sure up to 99min:99sec.
You can use it in your kitchen, study-room, and so on.
Even in background, it can work with "notification" feature.
In settings window, you can select the sound from preset sounds, and change its volume.
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Theres also free version, "Plain Timer Lite" in AppStore, without sound selection and volume setting, and with an ad banner.