| Business | Phone |
| Baxter & Woodman 31 Seymour Ave, Grayslake 60030 | (847) 223-5088 |
| Eltech Solutions Inc 888 E Belvidere Rd # 306, Grayslake 60030 | (847) 548-5330 |
| Encap Technologies 61 Seymour Ave, Grayslake 60030 | (847) 548-0600 |
| Eriksson Engineering Assoc Inc 145 Commerce Dr A, Grayslake 60030 | (847) 223-4804 |
| Erl Engineering 455 Yorkshire Ct, Grayslake 60030 | (847) 223-9842 |
| Great Lakes Engineering Co 888 E Belvidere Rd, Grayslake 60030 | (847) 548-3700 |