225 Pa. Code § 701 : — RULES OF EVIDENCEOPINIONS AND EXPERT TESTIMONY — Opinion Testimony by Lay Witnesses

If a witness is not testifying as an expert, testimony in the form of an opinion is limited to one that is:

(a) rationally based on the witness's perception;
(b) helpful to clearly understanding the witness's testimony or to determining a fact in issue; and
(c) not based on scientific, technical, or other specialized knowledge within the scope of Rule 702.

225 Pa. Code § 701