4 pin Bluetooth RF Transceiver Module

Projects Networking, Protocols, and Devices
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Hi all. I'll buy this module for control Arduino using the Android Phone: http://www.ebay.com/itm/Mini-3-3V-DC-Wireless-Bluetooth-RF-Transceiver-Module-4pin-RS232-TTL-For-Arduino-/261024357609?pt=LH_DefaultDomain_0&hash=item3cc6439ce9 I've one questions. Will it work? I read, that Arduino digital I/O pins operating on 5V voltage, but this module operating on 3.3V. Will I need a logic level converter?
Here is similar module: Moduł Bluetooth UART RS232 Arduino TTL - 2368811280 - oficjalne archiwum Allegro and the seller wrote, that it works on 5V too. Is it true?

Sorry for bad english.

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Arduino 5V inputs trigger at 3.0V. You can use 3.3V outputs to 5V inputs. If the 3.3V input of the device is not 5V-tolerant then you can use a voltage divider (two resistors) to bring the 5V output down to a value that the 3.3V inputs can handle. I have found that 2.5V (two equal resistors of 1K to 10K) to divide the voltage in half seems to work for 3.3V inputs.

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Thank you!