Im not real big on generic signs
copies of adt, or brinks signs are available on amazon.

adt https://www.amazon.com/ADT-Security-Aluminum-Aluminum-Stakes/dp/B08LHCLK6B/ref=sr_1_6?crid=32QGV2LO4JWJA&keywords=adt%2Bsecurity%2Bsigns&qid=1658945610&sprefix=adt%2Caps%2C471&sr=8-6&th=1#customerReviews

brinks https://www.amazon.com/Authentic-Brinks-Security-Reflective-Stickers/dp/B07WY492ZD/ref=pd_day0fbt_sccl_2/132-4945332-0062523?pd_rd_w=gyYJy&content-id=amzn1.sym.0a3d352f-2699-4ba2-810c-59dcb4abfa1b&pf_rd_p=0a3d352f-2699-4ba2-810c-59dcb4abfa1b&pf_rd_r=GZ92D1GQNT204PJWAVYW&pd_rd_wg=83aRp&pd_rd_r=a2a85afa-f3fc-481a-9261-8b7bbe29d0a0&pd_rd_i=B07WY492ZD&psc=1#customerReviews