All Philips OneBlade models can be used on wet or dry skin, with shaving gel or foam, or even in the bath or shower.
While dry shaving often products better results (because wet hair sticks to the skin), you can shave however you prefer. If you choose to use shaving foam or gel, rinse the blade with water regularly for best results.
Tip: while some products include a charging port cover, this is not the case for Philips OneBlade. You can use your OneBlade in the bath or shower without covering the charging port.