A whiteboard comprises a panel, four rims and four connectors. The panel comprises a writable pre-coating layer, a foaming layer and a back plate. The each rim comprises a rim main body and a number of locking pieces. The rim main body comprises a top plate, a light filter plate, an upper plate, a side plate. The light filter plate is connected between the top plate and the upper plate by melting. An inserting plate is vertically extended outwards from the side plate. A locking plate is vertically extended downwards from the rear end of the inserting plate. The locking pieces are locked at the lower ends of the locking plates. Each of the locking pieces comprises a connecting portion at the upper position thereof. A supporting portion is formed at the lower end of the connecting portion. The each connector comprises a bottom casing and a top casing. The bottom casing comprises a bottom casing main body. The top casing comprises a top cover. A lateral plate is downwards bent and extended from the outer edge of the top cover. A sealing strip is pasted at the position of the inner edge of the sealing strip contacting the writable pre-coating layer.

A protective mat is provided which may protect surfaces such as a table top from contact, penetration, or damage from objects or substances such as nail polish and acetone. A protective mat may have raised edge around the periphery to keep spilled liquid from flowing out the mat. A protective mat may contain shapes with raised ridges and recessed middle to act as a well for example in mixing various colors. A protective mat may contain other various shapes for the user to try out various nail art decals or use as a palette for example. A protective mat may contain a ruler and grid to assist a user in designing a nail art decal for example.