The remains are PT Klai's bones only. It's on the top part of the chedi and may people visit. We where there on a Sunday and it was really busy, probably it's quieter during week days.
As already mentioned, it's a big temple and you an wander around a bit, there's plenty to see and everywhere are small buildings, pavillions or even entries in the main chedi where you can find more statues of either PT Klai or other deities.
Above is a big statue of PT Klai's head with two 'Saam Ma Nen', the small statues had boxes in their hands and when you put some money inside, a tape played, praying for you.