Consider the following paragraph:

NAME_1 with DHL today I'll be demonstrating the sliding doors. They consist of two panels that slide horizontally along a track, with one panel typically fixed and the other movable. To operate the door, you can simply push the movable panel to slide it along the track, and the door will open or close depending on the direction of movement. In terms of servicing, it's important to keep the track clean and free of debris to ensure smooth operation of the door. It's also important to lubricate the rollers periodically to prevent them from wearing out prematurely. You can use a silicone-based lubricant for this purpose.

What are the different topics covered in the above paragraph? Give two different versions of responses. Please separate the responses with 6 asterisk symbols: ******.
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